Originally Posted by OptionD
So maybe what your partner is worried about is the possibility that your being with other men diminishes the amount that you require his emotional connection as you could be getting it from others. Also the perceived power imbalance in the relationship, where he may feel insecure about you having a more satisfying sex life than he is...
I would argue that is really is just about sex. Forget the emotions, men simply don't like "their" women having sex with other men. We like to have a monopoly on sex.