I'm not sure I want the time I'm doing it to be when she's had a fight with OM. I already decided next time that happens I need to stay out of it let her figure it out without any help from me.
IMO, I do not believe it is a good thing if the WW turns to LBH to discuss her feelings for OM and their "relationship". It shows no respect for her H, which is one of the major problems with a WW. I believe the H needs to tell her, nicely, that it is not appropriate and he feels very uncomfortable hearing her discuss her feelings for another man. If she continues as though he said nothing, he should say, "Okay, I need to go now, bye".
Actually, she wants someone to lick her wounds and tell her what a great person she is and how OM is nuts to let her slip through his fingers. It's not that hard to see her turning to the one she's been M to all these years. But a WW has narcissistic characteristics, and the LBH would do well to remember she is not turning to him out of love.
Even if WW and OM broke up, it would not fix the M. She would use you to secure her a place to stay, etc., until something else caught her eye. She though all she had to do was throw a ILY and that's all it would require for her to pick up where she left off in the home. However, her wayward nature was not ready to give up OM. Be thankful she didn't move back home and then go back to OM.
I have not observed a successful reconciliation whenever the LBH makes it too easy for the WW to come back. She has to go through a process, which usually takes quite a while. If the LBH allows her to use him as a rubber ball, she may never see him as the man she really wants.
I haven't known any healthy male who wanted to be the "rebound". Even in early dating years, I never knew any guys in school who wanted girls to see them as just a friend, love him like a brother, or date him on a rebound.......(only for her to talk to him about the boy she really liked).
What has changed that scenario is that now these are adults and there is a legal M and family involved.......which makes it worse. Somehow though, I think deep down........the dynamics, or makeup, are about the same.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!