[MF] Slept with my bestfriends boyfriend

So at the time my bestie was away for a month and her boyfriend was in some sort of training so he would come down every other week, my best friend suggested he would stay at my apartment since he got along with my boyfriend well, except my boyfriend was called into work unexpectedly and it required him
To be away for 2 weeks (agriculture) , I didn’t want to make my bestie stress out so I didn’t mention that and when her boyfriend showed up I explained and he was okay with it , it started off normal the first 3 days he was gone most of the day and just here to sleep on the couch ( one bedroom apartment)

But then I started having these wild dreams , sexual
Dreams . Me and my boyfriend hadn’t had sex in over a month mainly due to arguments so I figured I was sexually frustrated, but the next night I had a dream of me and besties bf let’s call him James . It was a really hot dream and I started to play with myself as soon as I woke up, it was around 1 am in the morning .
I walked out the room and noticed he was uncovered and I could see he had a boner as he slept, so anyways I go back to my room and start to fantasize again, I knew it was wrong but couldn’t help it. So I came up with a plan for the next night , I knew it was wrong but something I just needed to risk .

I [F] cheated on boyfriend with his best friend

This was when I was 19 years old, his best friend was 20, my boyfriend and I had been dating for about 2 months and we were both virgins , he was renting a small apartment living with his best friend so He was usually always around and every time I went to visit I always felt like he was checking me out , if I wore blouses that showed cleavage or dresses that showed enough skin he would compliment me and I never seen it as creepy , I always thought it was cute but never felt any attraction towards him. So one day I was having a pretty crappy day and went to his place except he wasn’t home , his best friend was though and so I texted my boyfriend to which he replied that he was stuck working for another 3 hours plus an hour drive back home ( LA traffic )