Depends. If I'm at home with my wife, 2-3 times a week, so that would be my guide at age 50 for sex in a steady relationship, although I would like it every day. Of course it was more like 4-5 times a week when younger. However I also have a married woman 'friend' when I'm away from home on business; we meet 3-4 times a week, about 10 weeks a year and fuck each other senseless each time, just for mutual enjoyment as she also likes it more often than she gets it at home. I also have the occasional recreational fuck outside these relationships. Unless someone has moral or religious reasons for not having this sort of affair just for sex, I recommend it when you (m or f) need it more than your partner.