Cheating on someone is deceptive and unfair.
Tom is in a relation but is finding himself more and more attracted to other women.
Tom wants to have sex with a gorgeous woman he recently met.
Tom tells his girlfriend he is attracted to another woman.
Tom asks the gorgeous women if she wants to hook up with him.
Toms girlfriend says she understands and tells him he is free to pursue her, they remain good friends and Tom ends up sleeping with the gorgeous woman.
She says yes, but finds out he is in a relationship and lets his partner know, she never meets him and his partner leaves him as well.