Brian Dunkleman -- Nuclear Custody Battle ... Assaults, Alcoholism and Child Stealing Allegations

Brian Dunkleman is in the middle of one of the nastiest custody fights in Hollywood ... with each firing various claims including physical abuse, alcohol addiction and child stealing.

Dunkleman says his wife, Kalea, is an alcoholic who is so out of control she poses a danger to himself and their 3-year-old son, Jackson. He says she has drunkenly punched him in the face and is now involved with a cartel drug dealer she met in rehab.

The former "American Idol" host says he was so fearful he took Jackson to New York last month, went to court and got an order giving him temporary physical custody, pending a hearing.

For her part, Kalea says it's Brian who's the abuser. She says he has picked her up and thrown her against a wall in front of their son and has verbally abused her, calling her a c***, an abomination and a useless bitch. And she says he's so abusive he once locked her out of the house and made her pee outside while he smirked at her.

She admits she's had alcohol problems -- she says drinking was part of her job as a publicist for big chefs like Wolfgang Puck, but she insists she's now on the straight and narrow.

Kalea is asking a judge to order Brian to immediately return Jackson to California.