'Little Women: LA' Star Briana Renee Leaves Cheating Husband

"Little Women: LA" star Briana Renee was fed up with her hubby's cheating ways, so she's finally called it quits ... TMZ has learned.

A source connected to the former couple tells us Briana broke up with Matt Grundhoffer last month because there was no way of resuscitating their 3-year marriage. We're told they found it impossible to bounce back from Matt's constant cheating and flirting -- some of which was seen on the show.

Matt copped to straying at times, and it sparked multiple fights.

Now, the hard part. Briana and Matt have a 16-month-old son together, and 2 kids from previous relationships. They're still living together while they figure out new arrangements, but they sleep in separate rooms.

We're told there's zero chance of reconciliation, and divorce is looming.