Information
The way we think is determined by the 'struggle for life' of our distant Stone Age ancestors some million years ago. As a result, husband and wife are jealous in different ways. She finds it more difficult when he has an emotional relationship with someone else than when he cheats. With him it is just the other way around: he condones a crush, but he cannot stand it when she does it with someone else.
Statement
Women are more likely to fall in love with 'someone else' than men, but are less likely to cheat.