It has everything to do with biology. Loyalty does not look the same between men and women. Men offer protection and provisioning to women in exchange for sexual / reproductive access. Man was put on earth to spread his seed. Telling a man to fancy one woman sexually is analogous to telling women to fancy short, broke, weak men.
No one is telling a man to "fancy" one woman. A man (or woman) may fancy many people throughout their lives. Married or not, it's human nature to be attracted to the opposite sex (or the same sex), no one is refuting that, I'm certainly not.
BUT when you take the vow of fidelity in matrimony, you don't act on that attraction, that is what is meant by having character and integrity.
You don't allow your thirst for the vagina or to "spread your seed" to override your sense of integrity, loyalty and the commitment YOU made.
If you don't want to honor the commitment or if you don't believe you have it in your character to behave with integrity and remain faithful, then DON'T make the vow. It's really that simple and there is no debating this IMO. It's a choice.
Marriage is not a need, it's not a necessity. You can procreate, have a family WITHOUT marriage. And in my neck of the woods, many couples choose to do just that and their kids are happy, healthy, well adjusted kids who are loved by both parents. In some cases more so than when their parents are married but unhappy and one or both are cheating.
All this noise about biology and men and women valuing loyalty differently is a load of *. It's an excuse to disguise the fact that some men are incapable of controlling their thirst for other women and keeping it in their pants and justify it by saying it's biology or men and women are different, have a different sense of loyalty blah blah. It's weak.
Unless you wrote your own marital vows and remaining faithful to your spouse was omitted from those vows, by cheating you are breaking the vows thereby disrespecting the commitment YOU made to your marriage, your wife and ultimately yourself.
