And the second time? Did the "alien" leave? Was your wife back for the most part, with improvements? Was she her loving self again? Surely she must have been, for it to work, but I'm just asking.
I'll briefly answer your questions. It was no longer up to my W for our M/R to continue. I had done the work and had moved on. The tables had turned.
So I wasn't so anxious to let her back in until I believed her changes were genuine. And I had to take our kids into consideration. Otherwise, I would have been content going my own way.
Today, I can say that I don't regret working on our M or even going through the mess. We are both better because of it and so is our M. Many lessons learned.
It took hard work to change behavioral patterns, and improve relationship/communication skills. I will always suggest to identify issues and work to address them. Be the captain of your ship.