Envy and jealousy aren't the same. (Sometimes I get annoyed that I can subdivide these so finely in English but I need to borrow from Greek to discuss love.) Jealousy would be a situation where I did not want my wife and the new guy to be happy; because I felt she was mine, or because I was not. I think I feel relatively little jealousy. I can hope that I'm wrong about how bad he is for her. I can think of several guys I'd be reasonably happy to see her with.
But Rogue Bambi in comments to the Forgiveness post made me realize that envy is where I have the bigger problem in this case. One of the things that had bugged me in our marriage is that I could not get her to wear costumes she wore at conventions at home for me. But she will apparently wear a slave collar for him.
envy (noun) 1. Resentful desire of something possessed by another or others (but not limited to material possessions). (Definiton from Wiktionary.)
I feel resentful desire for what she will do for him but wouldn't for me. I believe that would have changed everything. I have to face this down in myself.
I also have to face down her part, so I can forgive her. And so I don't exaggerate my own fault in the breakup, which I am prone to do. Because that sort of withholding in marriage is behaviour that I find wrong and contemptible; I would accept no such thing in myself, and I explained before we were married that I would not respect any such attitude in her.
Things like the costume thing have also always made it difficult for me to accept what she said about how hard she tried. There were a good number of things she did for me; they just were not what I asked for. Perhaps she was trying to get me to accept the real her, without being told that was the choice before me.
If I don't face her faults, if I just gloss over them and pretend they never happened, I cannot forgive them.