Men and women react differently to temptation when involved in a romantic relationship.  As reported by the Los Angeles Times:
In an experiment published in the Journal of Personality and Social Psychology in July, researchers at McGill University in Montreal asked 150 men and women to imagine chatting with an attractive member of the opposite sex. For comparison, another 150 imagined boring encounters with people of the same sex. After the visualizations, all participants played fill-in-the-blank word games designed to reveal subconscious thoughts.
Additionally, test subjects interacted with both male and female actors (participants were unaware they were actors) who were attractive and flirty or aloof, …read more