I've had those same thoughts too! My H and I are living together for a few months while we are fixing up, and then selling, our historic house, and it is rough, but I feel like he can see me GALing and it will be easier if his relationship with the OW ends and she is married with kids so I think that increases the chances of that affair breaking up, so I believe that is a possibility.
On the other hand, he seems to blame me right now for every mistake he has made in his life, not being a very good father, the kids being autistic, etc. and I kind of think that kind of thinking leads to his thoughts that then a divorce will lead to his life being perfect or nearly so which of course it probably won't. He and the OW will then have real relationships instead of the fantasy they have now and they'll discover they both have flaws (many many flaws in my H's case)! But my H is going to have to have all of this on his conscience, the affair, the separation, and the divorce, so he is going to have to initiate everything, is how I feel about it all, at least at this point, even if I may have to go through a lot of pain and therapy to get through it all!!! Karen43