I couldn't care less tbf- it's him she should be angry at
Yes, it is him she should be angry at.
But ... you couldn't care less?
Corking. So you have learned nothing, feel no shame, & if this man came crying to you in desperation needing his ego soothed by proving you do still actually fancy him - you'd take him, wouldn't you?
I hope he leaves his wife, 'loses' a crushing volume of assets to her in the divorce, & moves straight in with you. You'll believe you have "won". He'll know that you are just a handy roof & compliant body.
Because men who genuinely fall for their OW leave their wife cleanly, arrange their own interim accommodation while treating his ex-wife decently, & work hard to ensure that their OW - now new woman - doesn't suffer the backlash of rebound, or is being used as any port in a storm.
Enjoy being a port, OP. Probably one of many, either serially or simultaneously. Because this man is a user, but your startling "couldn't care less" reveals you in a similar light.
Or spend some time in therapy, understanding that the flip side of "low self esteem" can sometimes be selfish acting out at all you think the worlds 'owes' you.
And selfish people quite often get what they want, but remain deeply unhappy.