50% of men have sex outside a relationship.
25% say they don't, but do.
20% wish they could but won't (religious reasons, etc.)
5% don't (either they died right after the ceremony or have been institutionalized in solitary confinement)

The numbers are lower for women but are increasing.
I wonder if it's attributable to a change in societal norms or the internet.

My guess would be 65%.

What would the number for women be? Much lower, I would suspect.

We all thought we knew what sex was once upon a time.  Are you saying any type of sex? Fantasy,masturbation,dreams?  Everyone male and female.  If it is penetration it would be lower.

Hi Sedona,
I read a statistic somewhere and for the life on me, I can remember where it was that said that over 10% of a womans children are not of the father/husband she is married to.
It will be really interesting when DNA tracing is just standard procedure for all parants and children. I think the world will be surprised to find that females cheat as much as males. They just don't brag about it.

that's too high!  (At least in Germany)

With the boom of the internet age, I believe that the percentage has grown considerably.  I would never have attempted to be "involved" myself without the aid of the internet and sites like TER.  Picking up civilians from a bar or streetwalkers would have been out of the question for me.  My guess is 65% of men and 50% for women at least.

A recent TER survey (see "Are Your Married") concluded that 50% of TER's are not married.  (Of course it doesn't reveal how many of the 50% had significant others.)

http://theeroticreview.com/survey/viewresults.asp

Sorry I can't put my fingers on the study, but the last one I read (a few years ago) found that women "roamed" almost as much as men. The numbers were something like 65% (men) and 60% (women). If I recall correctly, the number of men dropped slightly from the previous study and the number of women rose substantially. I believe the subjects were all married for five years or more and the longer they had been married, the more likely they were to have "cheated". This was a major university study.

dawctor