Hormones Raging! Could use advice!

The very last night I was there he told me he didn't want to be in a relationship, I was heart broken, but I'm the type of person who just stays sting and goes on with life. 

I then found out I was pregnant at about 3 weeks and 4 days. I immediately called him first, the first week or so he was so supportive, and then he started questioning if it was his. Saying that he wouldn't be mad because him and I weren't in a relationship, but to me I very much considered us to be.

His ex fiancé contacted me in April asking me if the baby was his (they got back together briefly) I didn't see it until this week, I messaged her back and said yes and asked why she was asking. She told me that he was saying he wasn't sure it was his because I was out having sex with other guys. (Not true at all, I was head over heals for this man)  she didn't know I knew who she was, and she proceeded to explain who she was and why they weren't together. 

I tried really hard to let it bug me, but I can't understand why someone wouldn't want to be involved. I don't understand why he would say those things about me, and she's not the first person he's said that too, I've had multiple people message me and say that he said the same thing. 

It makes me want to not keep him involved, not that he really is anyway, but I text him updates every appointment. Ask him for name inputs etc. I even asked him if he'd like to be in the delivery room. All because I know it's not just about me. But tonight it's really screwing with me, maybe it's just hormones. Idk. Ugh. I'm having a crappy night guys!