Why does my husband feel like i'm trying to change him? And am I wrong?

My husband and I have been together almost 3 years, married 6 months and i have a daughter from a previous relationship. We had a very active sexlife in the very beginning, though we waited quite a while before becoming intimate. In the last 1 1/2 years our sexlife has drastically declined. I know everyones going to say he's having an affair, but i know thats not the case. Today he was talking about a friend of his going out to get some a$$ when i asked "why havent you ever been like him"... He immediately jumped down my throat telling me i was trying to change him. He says we arent intimate often because he respects me... But i just dont understand... Have any men ever felt like their wives/ gfs were trying to change them by asking for more sex?