Andy Dick's got a new arrest, and probably an ex-boyfriend ... after cops say he smacked the guy upside the head with a liquor bottle, leaving a deep cut.

Law enforcement sources tell TMZ ... police responded Monday to Andy's home in the L.A. area, where he and his partner got into an argument that escalated, and allegedly got physical.

When cops arrived they saw enough evidence to arrest Andy for felony domestic battery. He was back on the streets about 3 hours later ... once he posted $50,000 bond.

Our sources say this is the 2nd time in 2 months police went to Andy's place for alleged domestic issues -- he was also busted in October when he allegedly weaponized a frying pan! Cops say he hit his BF in the face with it.

The troubled comedian's legal troubles are well documented. He was sentenced to 14 days in jail for a 2019 sexual battery -- squeezing a random woman's butt on the street.

He's had a couple of run-ins with Uber drivers ... one accused Dick of grabbing his crotch in 2018, and that led to a misdemeanor sexual battery charge.

And, in October 2019, there was this bizarre street fight with an Uber Eats delivery driver. Video showed Andy getting his ass handed to him ... as the driver slammed him to the ground.

And, who can forget Andy notoriously threatening to grope and lick one of TMZ's photogs back in November 2017.