QUESTION: "Dear Ian:

I’m engaged to a great guy, we’ve been together three years, and we’re getting married in two months. The problem is I’ve started having sexual fantasies about his brother. It started with a sexy dream, and now I find myself sometimes thinking about him when I masturbate. The reason I’m writing is because last night I was having sex with my fiancé, and I was thinking about his brother! Help! The more I try to push the thought away, the more I end up thinking about it. I feel so guilty. Should I call off the wedding? Am I falling in love with my potential brother-in-law? "

ANSWER: You have to ask yourself if your fantasies are an indication of ambivalence about your impending marriage to your fiancé. Is there something going on that you may not be admitting to yourself. The fact that you’re fantasizing about his brother may not have anything to do with your sexual feelings for him, but could be a way of expressing doubt. Nervousness about marriage is natural, and it’s possible your jitters are expressing themselves in this manner. But if you love your fiancé and, on balance, you feel good about the wedding, your fantasy may be nothing more than a forbidden fantasy. It's the things we're not supposed to think about that often seem most alluring.

You say you’re trying not to think about it and unfortunately that’s a sure way to escalate the problem —the harder one tries not to think of a particular thought the more likely it is to become intrusive. In the mid-1980s, research by Dr. Daniel Wegner, Ph.D. at the University of Virginia psychologist studied “thought-suppression” in an experiment known as the “white bear study.” Wegner sat people in a room with a tape recorder and told them to say whatever came to mind, with one caveat: don’t think about a white bear. No surprise, people mentioned the bear constantly. The more they tried not to think about it, the more they mentioned it. Researchers theorize that by suppressing a forbidden thought, the brain never gets a chance to fully process that thought. Without full processing, the thought may remain unresolved and will keep re-emerging in the consciousness. So what can we take away from this? Don’t let your brother-in-law turn into the white bear. Give yourself permission to enjoy the fantasy, and more than likely it will pass. On the other hand, if you find yourself growing more and more attracted to your potential brother-in-law, maybe you need to evaluate the big steps you’re about to embark upon. The fact that it bothers you shows that you have a strong value-system; if you weren’t bothered by the forbidden thoughts, that would be another problem altogether. It's not the thought itself that needs to be examined, but your reaction to you’re your feelings of shame, guilt, fear and what those feelings might be telling you.