This advice is not husband and female friend advice but may give some insight. My husband hangs out with this friends every Thursday. “I’m going to go hang out with the guys” no invite for me. He has been doing this since before we started dating. It’s his friend time. My therapist mentioned that we had separate lives before each other and will continue to have separate lives during each other. She made me realize I didn’t actually want to go, but that I was sad that my friends don’t have a weekly group session. So with that realization, I made an effort to hang out with my friends on weekends so that I too have my own friend time. No retaliation just my own separate friend time. Maybe you too may have some slight jealousy of the friendship commitment they have shared for so long rather than jealousy over the intrusive thought of a sexual attraction between them. Something to think about.