My 2 cents.
Pejorative or not there are definitions, and we all use definitions just using the word pejorative shows the need for definitions:
What Is Considered Cheating (From a Man's and a Woman's Point of View)
https://pairedlife.com/problems/What-Is-Considered-Cheating-men-and-women-point-of-view
Broadly, cheating can be defined as being emotionally or sexually unfaithful to your partner who you are in a closed relationship with. Having intimate physical or emotional contact with another person is typically considered cheating.
What Is Cheating?
Broadly, cheating can be defined as being emotionally or sexually unfaithful to your partner who you are in a closed relationship with. Having intimate physical or emotional contact with another person is typically considered cheating.
Physical Cheating
Physical cheating is defined by one person in the relationship becoming sexually involved with someone else. Typically, physical cheating also covers simple physical acts of intimacy such as holding hands and kissing.
When my wife has sex with another guy:
I she cheating, YES, by most all definitions, though to be honest some definitions use as the criteria "secretly".
Though I don't remember the exact words used in our marriage vows I am certain is contained something to effect of "faithful unto others". That is a contract we made to each other in front of witnesses and co-signed via our marriage license/contract. Yes we can modify that verbally, but there is no such thing a verbal modification of a written contract. If we divorce and remarried with a new and different marriage contract with words we swear to like "not be faithful unto others" then it would not be cheating.