For relationships, personal issues, dating, crushes, exes, breakups, infidelity and any aspect of Relationships Ask a Relationship Question /r/relationships/ TL;DR My friend is cheating on his girlfriend, should I tell her? The problem is that this best friend (we will call him.
Remember he's innocent until proven guilty and that he's been an exemplary boyfriend so far. There's no reason for him to stop because his friends are slimy.
Anna* loved that her best friend and boyfriend were close, but she never thought that they would one day boyfriend cheat with best friend.