Monogomy is not natural and is unhealthy. People do it since kids involved in marriage or the chaos of emotional distress of spouse/other both much more unhealthy.
I have had a couple girlfriends that were highly sexual, needed/desired a little extra spice and variety and got it. VERY hot, erotic!
I am missing the jealousy gene. But have enough reason that if I had a little jealousy deal going my past experiences tell me that if I was dating a lady and considering moving to next phase of relationship, commitment, and discovered she had a real past of "cheating" I would be thinking hubba-hubba knowing she was likely going to be a hot little minx in bed with me!!!!!!!