Why are you giving her such a soft landing? Stop holding her while she cries over OM. This is disrespectful to YOU. It's a great comfort to her ("Well, at least H still wants me."), but you are not a consolation prize. You are a man who is deserving of a woman who will be loyal and wants you for you...not b/c you are what's left.
Tell her that the souveniers have got to go. She's wearing his t-shirt around you? Really? In your house? In your presence? Do you matter AT ALL?
She hooked up with a bad guy that she thought was going to give her something that was missing in her M. You can be willing to work on those issues b/c it's your M, too, and you have ownership in those problems. But you are under no obligation as a H, gentleman, human being to tolerate her whimpering over losing her BF. Cut that out!
Once you get those boundaries set then you can start exploring with her why she found herself in someone else's arms - not yours. What was she looking for? What did she say that you didn't understand or not hear over the years? How can the two of you fill each others' love tanks? What kind of new marriage will you have with each other?
But first...the boundaries. Greek
Me45 H46 T25 M22 S21 & 19 D13 Separated and filed 8/08 Moved home 11/08