The answer to headline is “not very much, quite frankly. And just 17 times a year.”
The Japanese division of the drug company Bayer recently published the results of a survey into Japanese married couples’ bedroom life. They interviewed 103 men and 103 women, all currently married, from each decade of life from their thirties to their sixties, excepting men in their forties, where they only had 102 people, making 823 people in total. The fieldwork was conducted between the 9th and 12th of June this year, by means of an internet questionnaire. No information is available on how the respondents were chosen.
Surprisingly, I feel, almost a third in some degree of a sexless marriage felt that sex was just too much of pain in the bum (figuratively, not literally!), much higher than the percentage who thought love had faded on either or both sides of the relationship.
Note also in Q12 and Q13 the difference between how people with experience of ED reacted versus the good intentions of those who had not.