A study in the UK has found that more men are too stressed for sex at the end of the day. It seems that 44% of the men surveyed have "lost their libido" after a hard day at work compared to only about 1/3 of the women. I would assume this equates to many frustrated UK women. The survey just happens to have been conducted by a company that makes pain relief medication.
We just took a survey in my household and 100% of the men surveyed responded that they are NOT too stressed. (sample size = 1, standard deviation = 0.0, margin of error = +/- 0%)