PoorYorick - these circumstances are unique. This OW is one of many.
All the more reason to direct all your (completely justified) anger, hurt and blame on your dickwad husband.
I get that you need a safe place to vent and I hope you've found it, knock yourself out. And ultimately, of course you'll make the decision of whether to get involved in her relationship, faith community and so on. My hope is that you don't, for the reasons I've stated.
If she wants drama, ffs don't give it to her. She'll delight in telling her fiancé that you're crazy, bitter, anything that supports her narrative. The only way to win is not to play. The only way to make her the pathetic irrelevance she is to your new, free life is not to play.
I'm not some monster wife who has driven him to this, quite the opposite.
Absolutely, I don't think anyone has suggested that. You've been shat on from a great height and I'm very glad you and your kids are getting out of there. Look after yourselves, you are the only ones that matter.