I wouldn't put up with it either, don't get me wrong. But I would choose the other way and talk to her husband. He was the one to approach you therefore he should be the one to receive your disapproval and criticism. I wouldn't let him off the hook easily, but I wouldn't meddle in his affairs up to the point of telling his wife in his place.
Facts: 30, female, bi, v-type relationship with Sward (husband, straight, mono) and Lin (boyfriend, straight, mono), poly-fi and co-primary.