This!
The problem is OP you are in the Now, the present and I have been where you are.
Coming up to my 3rd anniversary of D Day. After 37 years together.
He honestly thought ( at the time) she was his one true love. She was after husband no 4 and to be financially looked after. Only he couldn't see that through the limerance and love goggles.
I can now tell you how it panned out for my Ex and the AP.
He moved in with her. He was extremely cruel to me and nasty. He changed the narrative to save face.
He then set up a bar business with mostly his funds but she put in a bit but then made him change her from shareholder to joint director.
My ex MIL got in touch with me over a year ago and couldn't help telling me how unhappy he was, how he was going to leave her, how she did no work in the business etc etc.
However, he bought himself a new house end 23 but did not involve her.
He didnt move out though and she realised that she wasn't going to get half his house and needed the business to get some accounts done so she could get paid out.
His mother saw through all of it but he, being the coward he still is, just stayed. The exciting sex life had been gone for some time I know. She barely tolerated him too.
Then a few weeks back she ended it and kicked him out. Making it clear that he 'wasn't meeting her needs' especially financially. She thought we were a lot wealthier than we were and many said that at the time.
And I always thought I would indulge in a bit of 'shadenfreude' when the inevitable happened but I actually just feel sad.
Sad that our adult kids had to witness the destruction of their family home, the pain and emotional collapse it had on myself (so I wasn't the strong mother for over they knew for about 18 months), I'm sad for the loss of my financial security that we'd built up through 36 years of hard graft and self sacrifice and we'd just got to a place of financial comfort.
But I have no sadness for no longer being his life partner / wife as I saw the man he really was ( and I'd had glimpses over the years as he'd cheated early on and was a terrible flirt ) .
Some men get caught up in a sexual fantasy world and it clouds their judgement and the cruelty they are able to dish out to their life partners is shocking.
I'm ok now. And he's been playing victim recently with friends and family but he can't do that with me as I will never forgive him.
We had to have co tact recently due to a very sad family event and I just found him irritating most of the time. No love or pangs for the past at all.
When you are able, please read Chump Lady book or her blog.
Her perspective helped me enormously and therapy too.
Leave a Cheater, Gain a Life: The Chump Lady's Survival Guide amzn.eu/d/gmvv3tQ
What he is doing and how he is behaving is so common and as old as time.