This MILF is actually pretty cool with the MC walking away.
I mean, she did cut him a very harsh deal, but then again, he's the one who basically blackmailed her. And in the end, she actually seems to like his resolve.
Plus yeah, if she was willing to throw all her possible power away for her man back then, she's actually not that bad. in many ways, one of the least abusive female characters we've seen towards men.
If the MC gets strong, and at this point he should, I could actually see her being ok with the MC's sister marring her son.