Not sure the "changes" he is making matter at this time. He did a single act that was wrong. This has obviously hurt his wife badly. She is probably not going to get over this anger and rejection in the few weeks it has been.
As an example, when my wife and I were dating, she was angry when she found out that I had went to a "gentlemen's club" with my college roommates before her and I were dating. She was angry for a while, then she expressed her feelings that she felt it was degrading. I told her I would not go again and she forgave me. Oh, and I have not been back.
Kissing a co worker is a physical act and going to take more time to get past.
Now he may not choose to do this, but here's what I would consider. I would make an appt with a lawyer for about a week or two from now for the two of them to go. This will show her that he is respecting her wishes. Seeing a lawyer does not mean a divorce will be filed.
My thoughts would be to cooperate with her and see if she reacts positively. He also needs to change shifts, change jobs, or something to begin to regain his wife's trust. That's not quick or easy.
