I also would leave. Ive had a partner before who constantly accused me of cheating, even though i wasnt and it never stopped. We were together 4 years and it just got worse. In the end he beat up my best friend cause he wthought we were sleeping together. He needs counselling or you need to leave. Do you want to have these kinds of arguments in front of your little one?
Just ignore him when he says that stuff. Or just ask him if he is the one cheating since he always accuses you. Unless you did something to lose his trust he shouldn't be talking to you like that. If you did do something that lost his trust then its going to be a long time before he trusts you again and either you can give it up or prove to him that he can trust you.
Id personally would leave or ask him to leave. i think if someone truly likes you or loves you then they wouldn't put you done. Maybe he might realize you ain't taking that and neither will your child. I know it's alot harder then said but honestly why would you like living with that everyday. My bf is not romantic or affectionate whatsoever and it drives me up the wall but if you ever put me down I'd be gone Because I know there's other people out there that wouldn't talk to me in that why. Sorry my opinion