This is a good story, but you left one out. Women get tired of the same old, same old quicker than men do. This doesn't mean you need to go poly, but mixing things up and keeping them interesting is key to female desire.
"New findings showed that women reported similar intensities of desire and arousal to men, and 'a real shift in thinking' about females and monogamy. “We were taught that men were the ones who needed variety, but the exact opposite turns out to be the case,” says Martin. “Overfamiliarisation with a partner and desexualisation kills women’s libido. We used to think it’s only men who became sexually bored after marriage; turns out that’s not true. It’s when women get married that it’s detrimental to their libido.”