I want to leave my toxic relationship

He’s cheated so many times, even while I was pregnant, with a girl who had hpv/herpes nonetheless. It just bothers me he’d do that and risk passing it on to me and our unborn baby especially because he doesn’t use condoms. He’s stopped the cheating but I can’t get over the pain it caused me. It’s been almost a year. But he’s mentally, physically and emotionally abused me as well which is also hard to move on from. He gives me a problem whenever I want to go anywhere and needs to know how long I’m going to be and who is around me. Even when I go to my moms or my grandmas, it’s just ridiculous. He’s extremely narcissistic and I don’t like the person that he is and I’m just so unhappy in this relationship. The only reason I’m really staying is so that if he files for custody, he doesn’t get our son. I would be more than fine with visitation, but no overnights. My boyfriend works overnight and sleeps all day long and doesn’t even budge if our son is crying waking up from a nap, I just don’t trust that he’d take care of him. And his days off he stays up late and sleeps late, so all around I don’t like the idea of our son staying with him overnight without me. I’ve done every little thing for him since he was born, my bf told me he’s already been through raising a kid and I have to do it on my own so I can learn..... 😑 his 4 year old is also a little too rough with out 10 month old and my boyfriend doesn’t keep a close enough eye on them when they’re playing together. The thought of my son being under my boyfriends care without me around honestly just gives me anxiety. Especially since I basically take care of him by myself and went through my whole pregnancy by myself because he wasn’t thrilled that I was having a baby since he thought it could ruin his chance of getting full custody of his 4 year old son. I REALLY want to leave but I’m being held back. I wouldn’t say that I’m in love with him but I think I’ll be hurt if he starts seeing anyone else, and we have good days together which makes me feel guilty for wanting to leave. I just know I’ll be happier on my own. I just don’t know what to do.