Relationship issues

So basically me and OH have been together for a couple of years. We both cheated on previous partners - not with each other. We met through work.

We’ve now got a 9 week old baby together. I can’t shake this horrible feeling that something’s different. He swears on our sons life he would never cheat as wouldn’t do that to me or our son

I just don’t know why i feel this way. I find myself being snappy with him as get things in my head. I also feel like when I’m not trying he is really loving but then when I’m loving he seems off. He just says it’s because he feels as though he feels loved so he doesn’t have to fight for attention

I want this horrible way of thinking to stop

I want a normal relationship but I don’t know how

I now feel like when we do spend time together it’s because he feels he has to as to keep the peace as my trust issues

Please no harsh comments