I'm a 29-year-old straight male. My girlfriend and I have been together for four years, officially as boyfriend and girlfriend for two. We are very much in love. However, since the beginning of our relationship, my girlfriend has told me that she is not interested in being monogamous for her entire life. She has talked to me about this intermittently since our relationship began. Before we were officially together, she dated and slept with a couple of people, and I was ok with it (I didn't like it, but didn't make a fuss either), because that was what she wanted. Over the course of our relationship, she has made it very clear that I am her man, her #1 priority, BUT she knows that in the future she's going to want to sleep with other guys. She also has said that I would be free to sleep with other girls.

My question is, how do I get over this terrible feeling that I get whenever I think about my girlfriend having sex with another man? I try to be open-minded, but every time the idea is presented, I get a sick feeling in my stomach. I want to make her happy, and I want to be able to go along with what she would like, but the same feelings and problems come up when she mentions this. I'll admit that I'm afraid some or all of our own intimacy will be taken away. But I think, what it comes down to, is that I don't like the idea of someone else getting to have sex with MY girlfriend. Am I wrong to think this way? I don't think of her as my property, but we plan on getting married and I'm worried that this will be a huge problem. She says that variety is the spice of life and that I should get over this because i put too much importance on sex, when I should separate sex and love.

I just don't know, Dan. Am I making too big a deal out of this? I am very happy with our relationship, and our sex life. And she has told me on numerous occasions that sex with me is the best she's ever had, but also that variety is the spice of life. Which then makes me think, "Why would she want anyone else if I'm the best?" And honestly, it makes me feel as if I'm not enough. Any advice you can offer would be fantastic.

When The Best Isn't Enough

Christopher Ryan, coauthor of Sex At Dawn: The Prehistoric Origins of Modern Sexuality, was this week's guest expert in this "Savage Love." You can read his wise, kind, and helpful answers to people struggling with monogamy—and anyone who's made a monogamous commitment is struggling with monogamy—here. Christopher was also kind enough to answer a few bonus questions. His response to WTBIE is after the jump. You should click through and read it right after you buy Christopher's book.

Whether or not you’re making “too big a deal out of this” depends on several things. First, assuming you could overcome this sick feeling you get when the issue comes up, would you want a long term (possibly life-long) relationship with this woman, on these terms? In other words, is your reaction something you see as a weakness in yourself that you’d like to overcome, or does it represent a fundamental difference in how the two of you understand and experience sex and intimacy?

You sound like a sincere, thoughtful, self-reflective guy, so I’m going to assume the woman you love is similarly evolved, psychologically. She’s not going to change, and even if you could find a way to make her, that would only lead to resentment and disaster. Our greatest ambition for Sex at Dawn is that it will encourage young people like you to clarify their sexual nature before signing on to long term commitments they can’t get out of later without making a huge mess. It sounds like she’s very clear on who she is and what kind of relationship can/cannot work for her long term, so it’s up to you to try to take it or leave it.

As to your insecurities, since she’s already risked losing you by being up-front about her unwillingness to sign on to long-term sexual monogamy, I see no reason to doubt her when she says she loves you and that her intimacy with you is far more than she has with anyone else. One of the advantages of sexual experience (which she seems to have) is that you realize that sex isn’t magical. She’s never going to leave you because another guy has a bigger Johnson or screws her better. She already knows what’s out there, and she’s found what she likes best with you. It sounds like she’s offering you emotional, but not sexual monogamy. So now you’ve got to decide whether you want to try to disentangle those two issues in your own experience.

If you do, I’d suggest seeing this as a way to deepen your connection with her. Explain that you want to really understand her experience and share yours. Ask her to tell you about her experiences with other men and notice your feelings. Are you disgusted? Turned on? Afraid? All of the above? Tell her about some of your experiences with other women and explore her reactions. Watch porn together and see what she particularly likes or doesn’t. Maybe you want to go to a swinger’s club or party together and see how it feels to be in a room with people having sex. You might find that doing these sorts of things together helps transform this issue from something that creates distance to something that binds you together even more.

If this goes well, you might work out some ground-rules for dealing with other lovers. How much do you want to know? Do you want to know when she’s with someone, or just hear about it later—or neither? Do you want to try being with another couple together? (This might help you overcome the fear of the unknown, as you’ll be right there the whole time, with a safe-word that you’ve agreed to use if you want to stop at any time.)

If you can develop a relationship in which sex becomes something the two of you share—even when it involves other people—you might end up with something very special. But if this sounds like more trouble than it’s worth, you might want to seriously consider looking for someone whose views on monogamy are less challenging for you.