For me? 4 times a night is good, 5 is pushing it a bit - I am getting older, sadly, with all the recharge time fuss that entails. A guy has to sleep sometime, and work gets in the way of day time fun too.
This is a very common question, believe it or not, and should be looked at honestly. And, if you ladies will excuse me for a second, I am going to address the guys here first. The ones that read guyspeak either to see what you are asking, or to learn from the masters. The ones that have the full toolkit, but don't know a spanner from a hammer.
Foreplay is king, you idiots!
You want to have sex. Cool. Fine. Go for it. But if you are only concerned with your own pleasure, buy a bloody doll. Your lady should have blasted her brains out at least twice before you even get in the saddle. With a little restraint, and good timing on your part, there should be another couple of orgasms before you finish.
Gals are unfortunate, in some respects. Most of them are at their keenest just after they have had an orgasm. You gonna leave them hanging, or show that you are a proper man? Jesus H, man, have some pride in your skills!
Now, back to the ladies.
Guys get pretty much one shot, and it is complicated. Have you heard the phrase "blue balls?" Holding off for too long, for a guy, is in all honesty, total freaking agony, where having an orgasm is actually so incredible painful you swear off sex for at least a day. Add in stress, tiredness, indigestion; they all have a negative effect on the old sex drive. And the recharge times. Once a week is not good. But sometimes it is understandable.