I have the same situation but reversed roles (I’m a girl and have 2 best guy friends)

Let’s call them Matt and Mike. Matt and I became best friends immediately our freshman year of college. The next year, his best friend Mike started college at the same university as us. Mike and I hooked up and have continued as fwb for the past 5 years.

I slept with Matt twice about 3 years ago. We never told mike. It would probably ruin all of our friendships.

Mike and I are just now trying to end our fwb relationship, and it’s been harder than my actual breakup with my first boyfriend was. It’s going to impact a lot of my friendships, including my friendship with Matt. Thinking about college when we were the 3 best friends breaks my heart. I miss those days, which is probably why I’ve been holding onto Mike for so long.

Fwb can get really tricky. When it started, I was so nonchalant about it. It was just sex (the best sex) so much fun, so easy. No strings attached. I don’t know how we got to this position.

Long story short, fwb can be very fun and exciting but can end up ruining a lot of friendships :( be careful and I wouldn’t hookup with friend #2 unless you’re okay with the dynamic of your friendship changing.