I hosted Christmas on Sunday and my current GF and my ex wife were both over as well
While that isn't my preference, it is what it is.
Did your ex wife bring her new husband? Not talking trash, but to get that level of cooperation they need to feel like they’ve got something to hang their hat on. Usually if they have a new man they’ll be cooperative. I couldn’t imagine being in that situation myself, but life is funny like that.
In derricks case Id guess his first BM has a new man(or woman) and she’s financially set for life, so why not cooperate? From social media posting her and Miracle Watts chick dated for a while, so maybe she like messing lighter women too and Derrick keeping them both happy?

And his second wife came into the picture after that train-running extortion story broke, so she knows what type of dude she’s got.
One of my wife’s coworkers is an Anesthesiologist, and he has this type of arrangement. Lives in Beverly and they both live with him, but the house is big enough for them all to cohabitate. It works for some.
