J.M.
oh gosh! That is quite a problem! Well as difficult as it is PERSONALLY, I don't think you should get involved. Offering the "victim" daughter a shoulder to cry on and advise as how to move on is one thing, but you can not shun the elest either. This was a decision both your daughter and the younger daughter's husband made together. For the youngest...I would say in due time she will let it go. She never really had him if he went off that easily. And chances are he will leave the eldest too. Once a cheater always a cheater. And I learned that from experience. I don't think he should be welcome at famoly gatherings just because the entire family doesn't need to be physically exposed the pain the younger woman is feeling and I think the older daughter should let him go too. Not because of what she did to her sister but because he obviously is no catch. I think the relationship will run it's course and some time down the road both woman will take it as a learning lesson. Given she will never trust her older sister again but that is the price you pay. Good luck!!!