I also came to the decision to end our M even though the OW dumped my H and he wants our M back. The problem is that H has not ever been humble about the A or accepted responsibility. He lied for weeks about the P part and then has only admitted they were together physically once. What a laugh. Either way, nothing in the last few weeks has shown me that anything has changed. The continual lies are the biggest teller of all.
I have been struggling with the moral aspect though. I did some soul searching and my H is not a believer. Biblically, it says that once a non-believer is gone, you are to let them go. If he was a believer, I think the outcome would be different.
I am sorry you have to move on but I wish you the best. However, I also admire those that stay and try to repair their R. I am trying to sort out how and when I can forgive but will get there eventually.