I was friends with this particular woman for a few years before she met a friend of my wife's; dated him, and then married him.
What I know about her; her now-husband has no idea...
When she was younger, she dated a "naughty boy." He started taking her to a sex club. He introduced her to threesomes (MMF). And then swinging. Most of their sexual experimentation involved other people.
It wasn't until he set her up for a gangbang that she realized she was in a toxic relationship. It started out with just one other dude pounding her from the back while her "naughty boy" watched; then another dude showed up, then another...and she ended up getting pounded in every orifice by complete strangers. Afterwards she decided she'd had enough...
Because it was clear she'd gotten "caught up" in a toxic relationship, I'm taking that one to the grave.