Well you initially didn't say that. So you're not a side ho. Congratulations. I mean it...Good for you.
I still don't think its your place to let her know anything. This is not about her. She may already know or will find out in time. You are not her counselor. In this case, worry about yourself and be glad you didn't get involved with this two timing loser and move on with your life.
I don't have issues. You're the one who came on line with a confusing situation to get public opinions. Side chicks should stay in their positions. You claim you're not one. Great. Move on. You're obviously in your feelings, feeling some type of way because why do you deem it necessary to do all of this? Let it go. Its not your problem.