There he is as beautiful as you'd remembered. You are about to lock lips with your sexy-as-ever ex-boyfriend, when a BEEP, BEEP, BEEP interrupts the moment. Oh, it's your alarm clock. Your trusting husband is lying there sleeping just where you left him.
If you are like at least some other women in long-term relationships, you might find that you have these dreams right before you ovulate. After all, Elizabeth Pillsworth, Martie Haselton, and David Buss studied women who were not on birth control and followed their monthly pattern of sexual desire for someone other than their mate. These researchers found that the women who were in longer relationships had an increase in desire for someone other than their mate as they approached ovulation.
Pillsworth, E., Haselton, M., & Buss, D.(2004). Ovulatory shifts in sexual desire. The Journal of Sex Research, 41, 55-65.