My boyfriend said he might hit me if I cheat on him, should I be worried?

A few nights ago I was very high on a medication I take for panic attacks. I don't remember much of what my boyfriend and I were talking about all I remember is him asking me if i would cheat on him. I said yes.. I'm not sure why i said yes, I've never cheated on anyone at least not physically, emotionally yes. he then said that if i did that he would beat the guy up and he might beat me up too. I've never met my boyfriend. we met online and he's 36, I'm 22. were friends for a year befor any thing romantic happend between us. should I be worried?
My boyfriend said he might hit me if I cheat on him, should I be worried?
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