There are all kinds of different people out there in the world, and how they choose to initiate, maintain, and define their relationships will contain multitudes. Part of a healthy relationship is a mutual agreement to what constitutes their social contract with each other, and consideration and respect for that agreement.
Depending on how seriously they take the game, I agree that it could be considered cheating. At the same time, I also agree that there are probably many more people in the world who wouldn't see this as cheating, and even less people would see it as cheating if it were handled over a series of emotes in a text chat instead of graphics and sound.
Or maybe when the guy was caught, it was simply the look on his face that told her he knew he'd been doing something unacceptable in the context of their relationship.
