Chemistry: I read a story about a couple who opens their house to online couch-surfers when one of the partners is away on a business trip. When I read that, my first response was, “Wow, something like that would never fly with me.” Their relationship has an incredible amount of trust, but I don’t think it’s fair to assume that everybody can reach that same level of freedom. So, if you’re uncomfortable that your partner has too many friends of the opposite sex swirling around them, I think that’s something you should accept about yourself. If it creates a perpetual climate of unease for you, then it’s affecting your chemistry, and you should probably leave.
Character: Before leaving, though, be sure to consider the character implications of your partner. First, look at the way your partner negotiates. How do they react to your unease? Do they respect and care about your feelings? Or do they demand you accept things for the way they are? If they accuse you of being overly jealous, are their accusations fair? Or are they willing to make compromises?
Second, inspect the reason your partner is surrounded by members of the opposite sex in the first place. Is it because they don’t get along with members of their own sex? Or is it because they feel unsure about you, and want to keep a lot of back-ups around? It’s possible that your fears are correct, and your partner is truly untrustworthy and has ulterior motives.