Very true. However, I do think Men are pretty much taught from puberty that they should always say yes. We Women are basically taught the opposite. There is social pressure on us to say no, but social pressure on them to always say yes. Men who turn down sex are never understood by their buddies, never portrayed well in entertainment or art, rarely even encouraged by those closest to them. Within a marriage, a Woman who turns down sex from her husband may have reasons pertaining to that night, but how understanding are most wives when husbands turn it down? Men are always expected to say yes. So then you put them in a situation where they have plenty of opportunities, and suddenly they have to learn "no". Some guys have an easier time with monogamy, and they'll be able to do it. Others, probably most others, won't.