Screw soap operas, Usher's child custody trial has all the drama a lonely housewife needs -- 'cause his ex-wife's lawyer dropped a bombshell in court ... accusing him of sexing one of Tameka Foster's bridesmaids.

Usher was being cross-examined by Foster's lawyer yesterday in Fulton County court ... about his claim that Tameka brings nannies in and out of their children's lives.

Tameka's lawyer asked Usher if one of the nannies in question had "left Miami because you were discovered in bed with Maya Fox Davis?" Sources close to the couple tell TMZ Davis was a bridesmaid for Tameka ... and the alleged incident happened during their marriage.

Usher's attorney quickly objected, but you gotta watch the clip to see how it played out in court. There's also a contentious exchange between Usher and Tameka's lawyer regarding that whole spitting incident.

The trial is in recess, and will be back in session in July. Until then ... there's always "Revenge."

Usher broke down in tears today in an Atlanta court -- after his ex-wife's attorney insinuated he cares more about partying than he does about his children.

Usher was on the stand for hours today in his ongoing custody trial with his ex Tameka Foster -- and during questioning, Tameka's lawyer whipped out photos of the singer partying in Europe in February.

Usher's fighting for more custody with his kids -- but Tameka's lawyer was trying to prove he'd rather go wild at a nightclub than be a good dad.

Usher was also grilled about his alleged drug use. The singer admitted to smoking pot in the past, but when the subject turned to his alleged ecstasy use Usher's lawyer objected.

Usher insisted he never used drugs in front of the children -- an allegation Tameka made early in their custody fight -- but hedged on the subject of seeing his children while under the influence.

The trial will continue tomorrow.

Usher blasted his ex-wife in court today -- testifying that Tameka Foster flew into a jealous rage, hitting him, throwing food, and worst of all ... spitting on his girlfriend.

Usher took the stand in his ongoing child custody trial with his ex, and under questioning by his attorney, revealed how Tameka once went ballistic and "wanted to fight" ... when he showed up at her house with his new sidepiece.

Ush testified Tameka walked to his car and said, "I'm gonna kick your ass. Bitch get out of the car. How dare you bring this woman into my subdivision in my house?"

He added, "She continued to spit. At this point she pulled the door open, tried to swing at her."

Usher claims he had to get out of the car and block Tameka ... who then hit him. Usher said he pleaded with Tameka to calm down, but claims "she threw a plate of food at the car" ... as he fled the situation.

You gotta hear Usher describe the intense showdown -- and remember, Tameka previously testified she once told the gf, "I will f**k you up."

Usher's ex-wife Tameka Foster will be out on the street in less than 60 days -- if Usher wants it that way, and she's totally freaked out.

Sources tell us, the couple -- who's trying to settle a nasty custody dispute -- is deadlocked in mediation, and the biggest bone of contention is Usher's Georgia mansion.

Tameka's currently living there -- but under the divorce settlement Usher can sell the property whenever he wants ... as long as he gives her a 60-day heads up.

We're told Tameka fears Usher is going to pull the trigger -- leaving her buried in legal debt with no place to live -- so she's asking him for a permanent home for her and Usher's kids.

Usher's response ... no way, no how. He says he's already paid her enough.

And that's why judges are in business. The trial continues later this month.

Usher's ex-wife Tameka Foster claims she never threatened to kill the R&B superstar, but she did admit under oath to saying "I will f**k you up" ... so you can see how he might have taken it the wrong way.

Usher and Tameka have been going through a bitter legal fight over custody of their two young children -- a fight that came to a head in a Georgia courtroom this past week.

Tameka took the stand and, as you can see in this video, was questioned by Usher's attorney about her verbal and abusive threat towards the singer -- where she allegedly said "I will kill you both," referring to Usher and his current girlfriend.

Foster went back and forth with her answer before coughing up a half-admission, saying she didn't threaten to "kill" him ... but admitting, "I did probably, out of anger, say 'I will f**k you up' and it's not acceptable."

Foster claims the menacing statement was a result of Usher gallivanting in and out of town with his new GF, which was "embarrassing" for her in such a tight knit community.

The trial will continue next week.

Usher and his ex-wife Tameka Raymond have gotten an ultimatum in their custody war -- they're at the Atlanta courthouse trying to settle it, and if they can't the judge is going to lay down the law.

The singer and his ex-wife showed up to Fulton County Court this morning -- where a judge ordered the couple to try and hash out a temporary custody agreement in private mediation.

They've had all morning to work something out -- but if they don't come to terms soon ... they'll face the judge again this afternoon ... when he'll impose a temporary order, deciding how Usher and Tameka will split their time with their kids.

The order will also address child support.

As we've reported, Usher and Tameka have been fighting over their kids for years -- Tameka wants full custody, claiming he secretly uses drugs. Usher has denied the allegations, asking for an increase in daddy time. The couple currently shares custody.

Usher says there is noooooooo way he is going to foot the bill so his ex-wife Tameka can pay for her legal battle against him ... this according to new documents filed in their ongoing custody case.

As TMZ first reported, Tameka wants Usher to write a check for $50,000 to cover her costs as the two trade legal shots in their fight for custody of their two children.

Usher finds that request absurd ... saying in court docs filed earlier this month that Tameka has consistently defied court orders and filed frivolous motions, like the one trying to force him to take a drug test.

Usher claims he's already forked over 25k for her attorneys and has shouldered the brunt of the financial associated with this case, especially when it comes to their kids.

Bottom line ... Usher feels Tameka's actions "directly harm the best interests of the minor children. Clearly, such actions should not be tolerated, much less rewarded."

A judge has yet to rule.

Usher's ex-wife Tameka Raymond is asking the singer to dig his own legal grave -- by handing over $50,000 to cover HER attorney's fees and other legal investments she's made ... to strip him of child custody.

Tameka filed the docs in Fulton County Superior Court in Georgia -- asking a judge to force Usher to pay her $15,000 to cover her expensive lawyer fees ... plus an additional $35,000 for other costs.

According to the docs, the other costs in their custody dispute include the retention of various expert witnesses, hiring private investigators, and procuring out-of-state depositions.

Tameka claims she's entitled to the money because of the vast disparity in income between her and her ex -- a disparity that puts her at a disadvantage while she's trying to build her case.

Tameka has been trying to get full custody of the ex-couple's two kids since December -- when she asked a judge to strip Usher of joint custody, citing a laundry list of reasons ... including canceling her Saks 5th Avenue credit card.

Usher is firing back at his ex-wife -- insisting he's a good dad who deserves to see his kids ... and NEVER cancelled her Saks 5th Avenue credit card.

TMZ broke the story ... Tameka Raymond asked a Georgia court last month for full custody of their two kids -- claiming Usher has continually dropped the ball as a parent ... failing to get her permission to travel with their kids, hiring nannies without her approval ... the list goes on.

Tameka also claimed Usher callously closed her Saks 5th Avenue credit card -- and now she can't take advantage of the "special benefits" the card offers.  

But Usher claims it's all BS -- filing his own response in the ongoing custody battle ... asking a judge to reject Tameka's request for full custody, on grounds her allegations are false.

Usher and Tameka currently share joint physical custody of the kids.

As TMZ previously reported, Tameka has also tried numerous times to get the judge to force Usher to submit to a drug test. So far, no luck.

We reached out to both sides for comment -- so far, no word back. A trial date has been set for February 27.

Usher's ex-wife Tameka Raymond is freaking out that testing the singer for drugs will soon be useless -- because the more time that passes, the more time Usher has to cleanse his system of illicit substances.

In case you haven't been following -- Tameka demanded Usher take a drug test recently because she thinks the singer is popping pills and who-knows-what-else around their kids.

Usher refused on grounds Tameka's demands were "frivolous and unfounded" and only intended to “harass and embarrass” the singer. But now, Tameka's lawyers are taking her case back to the judge in the ex-couple's custody war, pleading with the court to force Usher to take the test despite his refusal.

And according to the docs, Tameka wants the court to make it snappy -- claiming, any further delay will allow Usher to "cleanse" any evidence of drugs from his system.

So far, no word back from Usher's reps.

Usher's ex-wife wants to take away his kids ... claiming the singer has repeatedly blown off his legal obligations as a co-parent ... and even worse -- he CLOSED her Saks 5th Avenue credit card ... this according to court docs obtained by TMZ.

Tameka Raymond -- who had 2 kids with Usher during their brief 2 year marriage -- filed court papers in Georgia ... asking a judge to strip Usher of joint physical custody of their children ASAP.

According to the docs, Tameka claims Usher has repeatedly FAILED to obtain her permission to travel outside the state with the kids ... which he's legally obligated to do.

But there's more ... a lot more.

Tameka also claims Usher is required and has failed to:
-- get her approval before hiring nannies
-- give her first shot to watch the kids when he's away for more than 8 hours
-- allow her to take the kids for 2-weeks in the summer of 2011
-- let her have custody of the kids during Christmas break 2010

Tameka also claims Usher closed her Saks 5th Avenue credit card -- which he specifically said he wouldn't do -- and now she can no longer take advantage of the "special benefits" the card offers.

According to the docs, Usher also promised to pay $5k per month so Tameka could hire her own nanny for the kids -- but he hasn't paid in months, and now owes $34,000 worth of payments. 

Tameka also claims there has been a "substantial change in [Usher's] income" since they got divorced -- and because of his success, she should get even more money for child support.

A hearing on the matter is scheduled for Wednesday. Stay tuned ...