I'm sorry for the tough day. Of course you feel the grieving, because it's not what you wanted with your M. You fought very hard to save it and it will always hurt that it had to end, even if in the future you see that it was for the best.
As much as we say that it was a favor, and our lives are lighter and higher because we are not involved with the people they are now, it still hurts to lose someone who was a great presence in your life.
With time, the sadness will subside more and more.
Sweetie, I have no idea why. I ask myself the same questions. How could I have seen this? How did this craziness become my life? Why are they so mean to ME?
But, I am reminded again and again, with new information and support of all around me, that this truly has little to do with me. Also, that if this is more depression/bipolar, there really is little control they have and the M is not the only area they are self-destructing. You and I have both seen that with our H's. ABout the OP....your H stuck with one OW....in my case, it's an example that it's not the OP that could have stopped this or made it worst...he simply moved onto the next one and the next.....it was him.
I don't think accountability and other normal reactions come into play when you are living day to day, moment to moment, reckless and risky...almost wishing that it would all end with a death wish. Hoping you run into that wall that makes you stop.
There is something wrong...very wrong. And, in an odd sort of way, it helps to make it not so personal to you. It also helps you to see that there is no real "magic" awakening and suddenly becoming this amazing person. Also, you know, if it is a pathology, it would be a very hard life to live.
We got caught in a really bad car wreck. Now, it's time to walk away, heal and call the insurance company!