Cheating is ok as long as it doesn't hurt anyone else. Cheating would be for the most part considered unethical and immoral, but it is a form of learning and dealing with people. There are worse forms of cheating than others of course.
Cheating on a test isnt really that bad, you're only "cheating" yourself out of a good education which you can always get later. I tend to cheat on tests alot, not necessarily the old-fashioned look onto your neighboor's paper way, but by looking at old tests and asking people whats on them. This way I have an advantage, and I don't get caught. I don't hurt people, I make things alot easier on myself and I get ahead in school. So I consider this a good method of cheating.
Cheating on a boyfriend/girlfriend/wife/husband is bad. Sure you get your variety and get to mess around with another person, but this hurts the person you are with and can very easily destroy your relationship. I have cheated, been cheated on, and been the "homewrecker" that has ruined a relationship. No side feels good and nothing good comes out of this form of cheating.
There are also different kinds of cheating, but these are the kind that I deal with the most. I have a somewhat guilty conscience, especially from the latter form, but much worse things can be done besides cheating I think.