Life Is Short...But Not THAT Short

Since I live in a virtual cave here in NE Wisconsin, it's easy for me to miss things that are happening around the world. Despite the fact that I read five newspapers every day, things of note in society can slide by under my "Hey! That's Incredible!" filter. Such is the case with AshleyMadison.com.
This company is in existence solely, it would seem, to enable individuals to "hook up" for purposes of an affair. This is NOT EHarmony.com or any of the other "meet your potential mate" sites. This is about finding someone for an illicit affair, unbeknownst to your spouse or significant other.
As noted on CNN, there is a billboard which has sprung up (pardon the obvious allusion) featuring a picture of a man and a woman, both mostly likely bereft of clothing. The billboard proclaims "Life Is Short. Have An Affair." Needless to say, I was somewhat taken aback by this. I guess I was raised in a society that said having an affair was immoral and, generally, a bad thing to do. Maybe times have changed, and I missed it. The company spokesperson indicated that they were merely calling attention to what many people were doing anyway, and encouraging them not to feel guilty about it. The web site supposedly offers a guilt-free experience. Wow! I've really been inattentive to society.
Ninety percent of Americans surveyed indicated that they felt adultery was wrong. OK, I'll go along with that. But only 17% felt that infidelity was cause for divorce...huh? Statistically, between fifty and sixty percent of men will have an illicit affair while between forty and fifty percent of women will as well. What's up with that? If we all think it's wrong, why do we engage in such behavior?
And why shouldn't we feel guilty, having pledged to honor, cherish, etc. etc. "until death do us part."
Call me old-fashioned if you want to, but this affair business is none of my affair. Norms ain't what they used to be, apparently.