(F)How i made sure the guy i’m seeing with isn’t cheting on me or make a the side chick

i’ve been seeing this guy and he’s kinda cute and i really like him sm. we’ve been having sex almost everyday during our early dates but lately whenever we have sex he keeps calling someone else’s name.. so what i did was one night after we had sex i wen and grab my undies and hide it in his pocket cause i know that guy doesn’t check his pockets.. i thought if he was cheating that panty wouldn’t be there but if i was the side chick that guy be beaten to death so either way his ass is getting kicked