What should i do about my baby daddy situation?

I am 5mons prego, and barely showin. My baby daddy has been in and out throughout my pregnancy and i'm tired of it. ( I let him go about a month ago because of this). he just recently showed up at my door, didn't have my number anymore, and claims he came by to see how i was. he now says that i don't look prego, and that i'm a liar. He has one kid already, and told me he knows the time frame of pregnancy. This is my first child, and i know babies grow differently. I am showing, but then i'm not showing. It's crazy, but anywho he was my first. I feel like i shouldn't be with anybody but him, but he's not husband materal. I should've had better judgement, and not have let him took my Virginity. He's 22 soon to 23 and so childish. If he would have never contacted me again, i wouldn't have cared. I decided that i don't want him at the baby's birth or in my child's life. he says it ain't right, but what should i do? I depressed because i'm alone with this, and it really pisses me off. What can or should i do?