Personally I think the more adult thing to do would be to not play into her antics and just be nice to them all weekend.

I don’t really think it’s necessary to open your home to them. They are adults who can get an Airbnb, and I don’t think it would come as a surprise that this is what Anna wants them to do.

I'm not seeking to be actively hostile. I would be more than happy for them to come over for dinner. I'm just not okay with extending the favour of a free room to them.

Overall, I think as long as you two continue to be jerks to one another, you will continue to dislike each other. If your wife keeps her in her life, the right thing to do (for your wife) is to bury the hatchet and stop complaining about her.

I feel I have done what I can to date on this point, I have offered olive branches at stages.

You don’t have to like her or hang out with her, but you can be polite and indifferent

You sound impressively like my wife and I do remain civil.

say thanks when your wife gives you an out to go do something else. She knows you hate each other. Don’t make her stay in the middle of be drama forever

I agree. And for the most part we avoid each other. I wouldnt have an issue saying no to invite if I thought I would have ongoing contact with Betty; even without an out being given.