bongobaby I get why you are upset. You are questioning your entire friendship. You thought you were making friends, and now it turns out that possibly, you were just pointed out to her by her dh as a possible future shagee, and she befriended you purely with this in mind. This is what you are worrying about? Maybe it was like that, maybe she is looking for women to befriend for her husband to shag. Maybe they enjoy an open marriage, or maybe the husband enjoys and open marriage who knows.
Maybe the holiday was meant to be sexual, rather than friends taking their kids out somewhere fun. You have all these questions in your head.
But I think, (aside from him being a twat to approach you in your home to "talk about you and his wife falling out" and so being invited in on false pretences) at least he did not try to romance you and try to have an affair with you.
At least. That is the only good thing in the saga. He was open and upfront and you now know what is what. They are no longer going behind your back.
You can now move on without any sadness on your part that your friendship is ruined, because you know now there was no friendship. Not if she let her husbands desires come in and ruin it.
She could have said "Back off, she is my friend, and I dont want our sexlife come in the way of this friendship. I dont think she is up for it". But she did not. She did not know you well enough to stand up for you and shield you for this. She did not value your friendship enough.
At least that is what I would have felt (and did feel when a friend suggested similar way back when I was young and pretty)