I wasn't there - I don't know. If I were a betting man (and I've written a book on poker so I'd say I am) I'd bet the farm that he is using. But really, what does it matter? You are living in a relationship in which you have to pretend to be asleep to try and catch him because you know that you can't trust him and seriously, what kind of a relationship is that?
Is that that you want?