I don't get why he leaving her means leaving you too.
Can your partners get counseling? They desperately need all kinds of relationship skill development. It is also something they and you could work on without a counselor.
I also get you love these people. And you won't leave them. I suppose this could be where you learn what *not* to do in a relationship. It could also be where you learn that love is not enough to make a relationship healthy, safe, and joyful.