Baalei Teshuva with friends from the past

My husband and I are baalei-tshuva. My husband keeps contact with friends from his past, some of whom are women, and does not hide it from me. I’m not sure how to deal with this. I understand that one needs to respect one’s spouse, but where is the boundary? How should I react in the context of a Torah observant life? How should the home be run with regard to this topic? How should both of us behave with regard to our friends from the past? All the best and thanks in advance!