I'm not quite sure what it is your asking specifically, I will try to answer and if I don't answer ur question,
Everybody has different views of everything, my view is that any kind of affair is cheating.
If you are asking if every affair has to be physical, no it doesn't. There is a thing known as emotional cheating, this occurs when a spouse forns an emotional, spiritual connection or bond with a person of the opposite sex without they're spouces knowledge, either of the persons existence, or knowledge of a relationship.
An emotional relationship may or may not be physical; a lot of times if it hasn't already, this type of relationship does. More times than not.
An emotional affair can be more devistating to the spouse than a physical one, it can be harder to get over, to let the pain go and to forgive the other person.
I hope this helps