Love is too complicated for one person to describe. You have to choose what love is and what it means to you. Personally, I find that love is the feeling you get when you stare in your partner's eyes and say to yourself that they're the one(s) and that you'd do anything for them; even if it meant hooking with someone they love more than you.
And yes, I'm a supporter of polygamy. That doesn't mean I'm going to practice it.