<human>: Throwaway because all parties involved use Reddit.

My long time friend (we'll call him Paul) and I met on the internet when I was 13, and he was 14. We had really good chemistry and got along really well so we long distance dated on and off until I was almost 16. 

Fast forward to my high school graduation two years ago, and he flew up here to celebrate with me for the weekend. We ended up staying up really late (like 3-4am) every night and talking. I barely ate anything the entire weekend because I'm really awkward about eating around new people and he was also barely eating because he neglected to tell me that he was dieting for a weight loss challenge. So lack of sleep, coupled with lack of food, equaled bad decision making and we ended up kissing. No big deal, except I was in a relationship at the time, and felt super guilty. My guilt almost wrecked the friendship I had with Paul, and we didn't talk for almost a year, even after I broke up with the boyfriend I was dating when the kiss happened.

I've since moved out of my parents' house, and have my own apartment where I live alone. Paul is coming to visit again in a few months and he'll be staying in said apartment with me, this time for a whole week. I've been dating this really amazing dude (Lucas 22M) for almost two years now and I'm afraid I'm gonna mess it up when Paul is here by doing something stupid with him. I really really love them both, but I definitely don't wanna get with Paul at this time in my life because everything I have with Lucas is going really well and I couldn't imagine my life without him. How do I avoid history repeating itself with Paul, and level off my anxiety about his visit in a few months?

Condense the text into a few key points
<bot>: Friend who I used to date is coming to visit again, last time he visited I cheated with him. Now I'm with a different guy, but I'm afraid it's gonna happen again. How do I avoid cheating with him?