Cheater and trust issues

So my bf and I have been dating for almost 1 1/2 yrs now. Around 8 months in he went bar hopping w some friends and ended up kissing some girl right before leaving. He told me the very next day and said that he was so sorry and that he knew he had taken me for granted and he didn’t realized how much he’d been taking me for granted.

I figured aince it was just a kiss, and since he immediately told me, that is was forgivable. I have forgiven him but I’ve become crazy w trust issues

I trust that he’d never do that again. I fully believe that he wouldn’t cheat, or kiss, or do anything like that again. However, I’m constantly worried that he finds other girls more attractive and that he’s interested in other girls too. I’m worried that he’ll flirt or lead girls on.

Ig I just don’t trust him to just straight up cut the girl off or extinguish the conversation when it happens and it worries me. I want my bf to love me so much that he can easily turn down other girls and I’m worried that he will lead her on bc he doesn’t see a problem w it. (He’s never really done anything to make me think this other than that one night)

I only ever worry about it when we’re not together too. We’re an hour apart rn bc of being home from college and I get so stressed out.

How do I finally get over this trust issue?