I don’t think you’re a prude, just that you happen to feel the way you do. While some may take aversion to an open relationship to be close-minded, I think that most feelings can’t be characterized as a good or bad thing.
Me personally, I couldn’t be in a relationship that isn’t open. I love many people, and feel sad if I’m forced to restrict my love due to the jealousy of others. I don’t feel jealousy, myself, and will have no truck (be in a relationship, that is) with others who do feel it. I think that my openness to many is simply an aspect of my character, and “good” or “bad,” my partner must accept it in order to be able to say he loves me, all of me.
I’ve been with only one partner who has taken advantage of my lack of jealousy, and I never felt the “What, I’m not enough for you?” feeling. It had nothing to do with me, and it was just sex. We’re human animals – we like to have sex, and some of us like to have sex with many, many people. For certain partners, it makes sense that being with one person would not be enough. As long as I trust you to not bring disease into your life or mine, why be upset? The relationship is predicated on love, not on exclusivity in the bedroom. It is a licence, but it can’t be called cheating if lying is not involved.
I’m a hetero (if anything) female.
I am acquainted with the popular “knowledge” on gay lifestyle that you are citing, and can understand why you made that comment. However, I must warn you that in this forum, it is very likely to be taken as an extremely blanketed statement which covers a diverse group of people. You may have been correct, about a certain prominent percentage of the gay population, many years ago, living in LA or NYC. However, nowadays the situation has evolved not only in terms of popular perception, but also in fact.