My boyfriend cheated on me... please help me deal with this.

This is the third time that I am posting on reddit about this, and every time I do, I feel like I leave something out... so excuse me for the long post, if anyone can help me that would be great.My boyfriend and I (we are a gay couple) have been together for a year. On Oct. 21st, I walked in on him cheating on me with another guy. This was a major blow to my heart, I already have major anxiety problems and self esteem issues....Anyway, we ended up getting back together a week later. I’m still riddled with anxiety to this day. We absolutely love each other, he is doing everything in his power to make up for what he has done. He said that “past feelings” for this guy spilled over and he didn’t take into account he what he was doing at the moment and regrets every minute of it.We haven’t had sexual contact since July, and he says that he lost sexual attraction for me but he thinks that I am very attractive, physically and emotionally - and he says that he is working on it. I don’t know what this means. This was the first time he ever cheated. I’m not super worried about it because I expect that he will get over it, and I understand that sex isn’t everything in a relationship - but I understand it’s importance.We love each other, and I know that sounds so stupid, but we really do. That’s why I was more confused then angry when this happened.What he did has taken a toll on me mentally. I feel like I am going to be alone forever. I am haunted by the name of the guy, I keep replaying the scene in my head of walking in. I have absolutely no self confidence in myself. He used to tell me that i was the most attractive boy ever, and say that I should never worry about my looks and IT WORKED. It was the only thing that helped my anxiety - and now when he says that, I don’t believe it.I trust him to a point. I would say my trust is literally at 99%, but my trust for him was at 100% and then he went and cheated so I don’t know what to think.He’s in no way a “player”, he’s a sweet boy that cares about my feelings and is really committed to this relationship.I guess my overall question is: could have this just been a major fuck up? Should I trust him fully again?I’m so confused. Thank you.Edit: I’m 21, and he is 19 if that matters.