Need advice or input

Ja

I was dating someone for 3 months and fell in love for the first time. He made me extremely happy as I did him and it was as if we found our soulmate in each other. When we met he had just got out of a 4 year relationship that I didn't learn about until further in our relationship. His ex and her friends called me a whore and home wrecker because we started talking after they broke up and it bothered me because he didn't seem to put his foot down to her about it. He was still communicating with her and his reasoning for it was "he was trying to help her get over the breakup" which I think was stupid because he talked really bad about her like how she wasn't sensitive to his feelings and concerns. We had a pregnancy scare twice and two weeks ago we found out his ex is pregnant.

There's a possibility it's his and what hurts about it is the fact that he went back and had sex with her a couple days after our first date because he didn't have faith that we were going to end up in a relationship because we both made it clear we wanted to take things slow. About 3-4 weeks ago we had a 4 day break because he said that he was still thinking about the good memories he has with her and so he went and met up with her and told her about it. Then he goes back to meet with her because he went to tell her that he's in love with me and it was a mistake he just wanted to get over her completely so she doesn't ruin or have and negative effects on our relationship further. Not only that but because she's pregnant our relationship ended bc he wants to work things out with her so the child doesn't grow up in a broken home I understand that and I commend him for taking the action of being a responsible man for his kid but it amazes me and bring curiousness out of me as to if it's his child because in the first two months She was busy bashing me but didn't pay attention to her missed period two months in a row and she didn't call or text him to tell him about it she told their mutual male friend who then told him. So it's weird that after he told her he made a mistake thinking about her she tells their mutual male friend she missed her pet food instead of telling him the two times she seen him. I need someone to give me some sort of input because this whole situation is fishy.