The effects of patriarchy cloud women's natural inclinations. In nature, in many animals, and in all female primates they are incredibly sexually adventurous and promiscuous. Why not, it's a good evolutionary strategy? It leads to a better chance of healthy offspring.
In humans, it's finally been acknowledged that women get bored with monogamy before men. Men are actually quite good at accustoming themselves to what they have. Not so for women. They may like the social aspects and the coziness of monogamy, but it kills their libido to not have more variety. Well documented - from various studies from around the world.
Maybe we could get along better if men would stop telling lies about how things "naturally" are for their benefit and enjoyment and so that they can control and disempower women.
