Confused, gay bf?

I love him to death, but this confusion he seems to be having affects me I feel depressed and it's more because of the cheating. No evidence of meeting up because I read the emails but it's still looking at other men's dicks and saying he's "curious"  or "first timer" 

I pretended to believe it was a girl, and he begged me to stay. Tbh I really did forgive him and didn't want to push the gay thing as long as he promised he wouldn't cheat with Any human being ever. But idk :/ something is missing. I always feel suspicious I feel distant I feel useless like I'm not good enough I question everything. How do I regain trust if he can't admit a problem and please keep in mind that I am trying to stay with him.