Ushikubo suggests five traps you can lay for your unsuspecting man, explaining how the guy’s response will show whether he’s cheating on you or not.
Good guy: Changes the subject because he doesn’t really care who watched what with who.
Good guy: Doesn’t try to take it off you.
If he’s cheating on you, though, he’s probably quite a good liar.
Cheater: Agrees with you and sympathises with the cheating guy.