I think you need to define your parameters a bit more here.A friend and I were having a discussion about the effects of the lack of sex on a man. The both of us are 57 years old and our wives are happy with sex usually no more than once a week. He said he can tell over the last few years that his desire and also the firmness of his erections has started to be effected from the lack of sex. Neither of us were really sure if this is true or not. He is in pretty good health and just had a complete physical so he doesn't think that has anything to do with it.
We are interested in your opinion but would also like to know if you have any scientific/health information on this matter. Any thing you can contribute to our discussion would be appreciated.
If you are asking if there is a long-term affect of once per week sex on men on average, I doubt you'd find there's any coorlation. An average married couple has sex roughly 100 times per year (that can fluctuate somewhat depending on what study you read) in North America, so while you are having sex about half that often, for your age range it's likely not that far off normal.
That said, you should be looking at the effects on you, not the average guy. Some guys are fine with sex once every few weeks or even less, while others seem to need sex a few times a day or they'll start acting like a crack addict on withdrawl.
There's no normal, so what ever affects you is what you need to focus on.
I honestly doubt there is a big long=term affect for men in general. Look at monk's for example. I think it depends on what mindset you get yourself into regarding the lack of sex. For monk's, no sex isn't a big deal. In fact, they likely look at it as a victory (remaining pure, etc.) For another man, if he has no sex for three months yet dwells on that fact for hours each day, it may drive him mad.