So plate of 3 months just send me a message saying: "I still talk to my ex because blablabla." But then she asks: "Is that ok with you?"

What is the best course of action here? Just saying alright and keep fucking till the plate breaks or be playful and say something along the lines of: "Go marry him, he got some nice blue eyes." And then proceed till the plate breaks? Or actually keep her open for LTR material for now because she does have a bunch of green flags.