Most married couples don't maintain hot sex lives. I know this because every married couple I've ever met is shocked that my husband and I seem to still be in the "honeymoon phase" apparently to them the honeymoon phase means physical affection and evidence of mutual sexual attraction. Also 61% of Americans are either obese or overweight.
I'm not saying people cheat cause their partner gets fat, but come on, the numbers aren't really that far out of line with that possibility. Though I'm sure it's far more complex than that.
Posted by Yoga Nut on the My Fat Spouse Forum
Some people can't and shouldn't be monogamous. They've allowed themselves to get into a social agreement that goes against who they are as people, what is required for those people is honesty and perhaps opening the relationship.
For people who want to be monogamous and aren't just under social pressure to be so, then a bad sex life is often the reason a partner goes to get sex somewhere else on the side. That would be the most practical reason for introducing a new sexual partner into their life. Don't you agree?
The level of emotional attachment between partners in an affair is kind of a non-issue, since not all people can have sex detached completely from emotion, and sooner or later most people develop some emotional attachment to the person or persons they are physically intimate with.
But I would venture to say, and I could always be wrong, but I would say statistically, except for those cases where the desire to be monogamous isn't genuine, a couple who has a hot sex life isn't looking elsewhere.
Most human beings have other goals in life besides just sex. If you have a hot sex life with your partner and you have any type of career ambition at all and any free time to yourself, chances are good you don't want to fill it with yet another responsibility.
Relationships are complicated. They become even more complicated when an affair is added to the mix. This is more energy than most people really want to devote and if they were happy at home, they wouldn't be devoting it.
I know this from personal experience not just theory. I was the sole confidant of a friend who had an affair, and I myself was temporarily in an open relationship. The level of energy it takes to maintain two relationships on the sexual level is insane. Especially if it's open (I kind of understand the secret part of affairs because its way too much energy to have to constantly reassure your partners you aren't leaving them for the other.)