Personally, emotional affairs are 10 times worse than a physical affair to me. I'm sorry she did this to you. Have you asked her for counseling? Has she even given you a definite reason as to why she is so interested in this man? I understand having crushes every now and then while in a relationship. I have had little crushes before but never to that extent. She almost sounds a little obsessed with him. Like this has passed a simple crush or even emotional affair. I hope you can figure out whether you want to stay and work it out or not. This is a lot of hurt to overcome and, hopefully, she is willing to do the work needed to fix it.