The legal battle between Paula Patton and Robin Thicke is getting ... worse.

The actress is accusing Thicke of domestic abuse, infidelity and drug use. In new court documents filed in New York, Patton says Thick physically abused her, threatening to "bash [her] f-ing head in" and that he cheated on her multiple times -- once even bringing a woman into the hotel room where they were staying and attempting to sleep with her in front of Patton. The only thing that stopped him was that he couldn't perform because he's used too much cocaine that night.

Patton also claims that after the couple separated, Thicke had a "manicure and pedicure party for ... six naked women in our family home." In a separate incident, when they agreed to divorce, Thicke, 39, said he had "very little money left and that he would most likely end up living in an apartment in the Valley."

This entire dispute stems from the custody battle over their son Julian, 6. In fact, Patton is still being investigated by the Los Angeles County Department of Children and Family Services for emotional abuse of Julian -- with Thicke claiming she has "intentionally tried to alienate Julian from Robin."