Dear Laure:

Probably not a good idea to tell her. If you care about her, get to know her. If you do get to know her you may find out she already knows and endures him cheating on her. Or you may find out that someone else told her that her boyfriend cheated on her and she doesn’t believe it. You may find out she sees only what she wants to see, as most people do.

Or you may find out she cheats on him too.

So get to know her before you tell her. If you don’t intend to get to know her first, don’t tell her.

anita