Cheating definately hurts bad, but some people take the littlest thing as cheating. In your case, I agree with you. There is a big difference between having a regular sex partner (or 2 or three) besides you and a chance incounter that happened out of a situation and won't be repeating it's self.
Some people think it's cheating to have friends (not sex friends) of the opposite sex, looing at or looking at erotica.
You can be cheated to the core, and not have had sex been involved until after the fact, Like I was.
Imagine being cheated in every aspect but. My ex cheated me out of my finacial freedom and credit rating. The person I trusted was supposed to be paying the bills with the money I was out working hard for. I was at work when the mail came and didn't question it. It didn't take me long after she "went to take the kids to visit her sick mother", that I came home to the mail still in the box and finding the house payment 120 days behind, what were supposed to have been monthly bills in 4-5 figures and my savings drained. Like I wasn't going to figure this out?
Imagine being cheated out of any social status in a small town, as your ex had you labeled behind your back as a wife beater and child molester. Can you be a mild mannered person, and imagine this happening to you?
Can you imagine someone cheating you out of your children, that they did not want in the first place, having to go deeper in debt to have international kidnapping charges pending, before you got your kids back?
Can you imagine being cheated out of your dignity, as anyone who found out I had sense to go get therapy considers me a looney toon? Can you imagine 10+ years of being cheated out of the freedom to just answer your own phone as you had to let many bills go into collection, before you could satisfy them at a lesser amount while still struggling? Can you imagine having been responsible only to have to take 15 years to see any hope of rising from the ashes of a shattered existance?
All this, and supposedly there was no sex involved till after the fact.
Like I said, I agree with you. Someone who has a regular partner(s) outside of supposedly monogomous relationship is cheating, but I get so sick of seeing people whine about being cheated for things as having (non sexual) friends of the opposite sex, looking at naked pictures/video/webcams and such as cheating. I even feel for those who find their relationship in peril or gone because of a chance incounter fueled by unusual emotional circumstances and/or partying beyond normal common sense. Something that happened once, by mistake should be forgivable in the long term. Humans are sexual beings and don't always do the right thing at strange moments in life.
Cheating goes far beyond sex and non sexual cheating can be the worst kind. It was for me. It wasn't sexual cheating that ruined my life. That would had been a whole lot easier to get through than things beyond my control that I still sometimes find myself paying for emotionally and financially some 15 years on. Having loosing your love because they were seeing someone else hurts, but that hurt soon fades. Other kinds of cheating can haunt you for decades.
I hope it gets better for you :-)
PS to other answerers:
Stop the men bashing. I have known in my personal experience of far more relationships ruined by sexual cheating on the woman's part, than the man's. In my obsevations, women are far more likely to cheat sexually than men, but far likely less to get caught.