Everybody holds thoughts of having an affair, it was just that some of them were lucky enough to follow through on it while some weren't. Moreover, once such a thing happens, in comparison to a man, it was always easier for a woman to find a reason to justify the affair and accept that reality quite quickly. Just like how the adage went - Life is like rape, and since you're powerless against it, you might as well enjoy it wholeheartedly.