Help! Prepping myself and D12 for pending OW skank/Exnh for few phase of pain/re-marriage - Advice sought please

Exnh and I are finally D. Have daughter 12. He hooked up with OW skank immediately after he left our home and is now acting like brand new family with her. We were together 18 years married 16.

D12 today said she had a dream that he got married to OW....and I said "yes. you probably need to prepare yourself for that next". It was a reminder to me, that I myself need to prepare myself for that. She also said "He did not want more kids with us, and now (with OW), he will have 2 more." - i.e her kids. But, to keep her money tied to him (she never had to work and inherited all her money), he could possibly get pregnant with her.

This is an extraordinary statement for d12 to make, and a very, very painful one for me to accept. He stalemated me on having more kids and now its too late for me. But, now he will likely create this magical "new family" for our daughter...and I will be the one who - in the name of saving my marriage all those years - abandoned my desire to have more kids and have to accept that fate.

It all makes me sick. And most days, I know I made the right decision to leave Narc finally. But, as I see his utter and complete disregard for me, our daughter, my family, our history play out to the astonishment of all who knew us(even those who saw it all and never like him cannot believe the new levels of pitiful and selfishness he displays). I know I have to accept - and be strong enough to endure - anything from here forward that he will do....likely get married within a year of our ending, and my daughter will now become a part of another family.

I am detached and I am healing. Everyday I am stronger and everyday I know I would NEVER< EVER have had the marriage I wanted nor his love. EVER... BUT HOW - HOW? - in god's name do I EVER get to a place where all of this does not kill me?