When I was younger and still in the closet, I had a girlfriend but also a boyfriend, more for show, but a good friend of mine. Closest I have ever come to being poly! Don't think I could do it.. Hell, I like to be the center of someone's universe
.. but I respect those that do. And I have to second what someone said earlier, if I was single I do not think I would broach the topic of dating with someone who is poly, no matter how much I may like them - would recognize I couldn't be their everything, and that would be that.
