Cheating? Or not?

Ok so being pregnant my emotions are all over the place. But I kinda need yalls help. Before we got pregnant my husband and I got into a HUGE fight about him going to "work" at an old crush's house. They had a fling but supposedly they never hooked up or anything. He didn't tell me about this, I found a text and asked him about it. He denied, denied, denied and then finally admitted to going over there. Needless to say I lost my shit. Well we conceived that week 😳 I know right? So we haven't talked about it for weeks. It still bothers me but mostly it just opened the door. I lost a lot of trust with him.
Bottom line: My gut tells me he would never seek out an opportunity to cheat on me. 
My head tells me, don't be stupid he's a man. No matter how much he loves you he would cheat if it made his dick happy. (Pardon the language) 
What do yall think? . I'm not asking about this one specific incident, I'm asking in general.