The War at Home - Season 1 Episode 3 High Crimes

When Dave notices how nice Hillary has been to him recently, he is certain it's because she's having sex with someone. However, Mike spies on her and confirms that Dave is actually wrong. Dave then comes to the conclusion that she's smoking his pot when he notices his stash has gone missing. As he's confronting her about it, though, he accidentally tells her that it's his, but quickly tells her that it's not really his - it belongs to Vicky's mother, Betty, that she uses for medicinal purposes.