It’s all about intent. If the intent is to gain some romantic connection by liking a picture or something, it doesn’t really matter how successful it is at achieving that goal. Same as if you are at a club and try to kiss someone but they dodge it or something - you still tried to cheat, you just happened to fail. The point is you’re trying to get romantic validation outside your relationship (that you and your partner have agreed is not OK) to some degree.

But if you see your partner liking someone’s post and you accuse them of cheating because of that alone, you’re an absolute psycho.

What is this big hang-up about fidelity ? What makes being faithful the greatest friggin’ virtue in the world ?

-Joe Gideon in All That Jazz