FH had never been cheated on, but I had. It honestly didn't even bother me though because by the time I found out about him cheating, I was so done with the relationship anyway.
Then I dated a guy for a few years and I actually ended up cheating on him with FH, who was our mutual best friend. Messy situation but the only reason it happened is because we were in love. I'm completely against cheating and would have never even thought to cheat but I just couldn't deny it any longer. I left my boyfriend the next day to be with FH because I couldn't act like everything was fine. FH completely trusts me because we've been best friends for so many years and he knows the only reason I cheated on my ex is because it was with him.