As an unmarried woman, I set boundaries with my male married friends (heck even if they have a girlfriend who lives with them). I want their wives and gf's to feel comfortable around me. So, I always text or call their wives before I call them so they will know the nature of the call. If they stop by my home they call their wives and let them know where they are and I am never alone with them. Marriages should be respected. It's not just about jealousy but a respect for the commitment two people make to each other.