I think the choice is too stark and extreme... I think theres levels to cheating.
Theres.....
Level 1 - Inappropriate - when a SO flirts or allows or encourages flirting.
Level 2 - Disrespectful - when someone allows or makes their SO feel threatened or insecure about the relationship
Level 3 - ????? - I feel like theres one more level but i can't think of how to phrase or define it
then there's straight up CHEATING. But all those other things are putting you on the road to cheating.