Is why do men look for sexual gratification outside of their primary relationship genetic?

Historically we came from a tribal culture of numerous women per male as hunting was so dangerous the balance of males to females would have been lopsided. Then there is the need of men every three days but for women it's a few days per lunar cycle so a ratio of 2 - 4 females per male was not unlikely and there is genetic evidence that 8000 years ago it was more like 10-17 females per male.
It's only been in the last few hundred years that monogamy has become the law.

Gene from unique males on the left, unique females on the right.

Popular Science

An analysis of modern DNA uncovers a rough dating scene after the advent of agriculture.

FRANCIE DIEPUPDATED:JUN 14, 2017
ORIGINAL:MAR 17, 2015