Letting your mind drift to thoughts of someone else while you're in the act with your partner or spouse sometimes can evoke feelings of guilt. But are sexual fantasies something to worry about? Most experts agree that it's probably just fine - and even helpful - for you to pretend you're in the sack with Bradley Cooper or George Clooney occasionally. Something that excites you and heightens your pleasure, thereby making you more receptive to your partner, can be beneficial. Spicing up a stale sex life is always a good thing, as long as it's not hurting one of the participants. If you feel guilty about it, then take Dr. Joyce Brothers' advice: "It might relieve some of your guilt to know that many happily married individuals who have no thought or intention of ever betraying their spouse have sexual fantasies about someone other than their spouse."

And it is, after all, safer and much better for your relationship to keep the fantasies in your head than acting on them. The problem with fantasies comes when they overtake one partner's desire for the other. And if a fantasy is absolutely necessary in order for one partner to become aroused or have an orgasm, then it's definitely a problem. The object of your fantasy might be someone you know in real life, which can be a problem if you are willing to act on the fantasy and cheat on your partner. Examine the way your fantasies play out - do they involve aspects that are missing from your relationship? If that's the case, then your relationship could be in trouble. Perhaps acting out your fantasies in a role-play fashion can spice up your relationship and ultimately save it.