Sex and love are separate

I'm just wanting to see what your guys take on this is. So I know a guy that is in a relationship okay.... but his sleeping with another woman.. so I confronted him and said like you obviously don't love her so why are you staying with her? He then tells me that sex and love are different and that he still loves her, and the other girl is just sex..... does that make any sense to you guys? His like when they have sex they just have sex they don't kiss or anything... but that doesn't change the fact that his able to sleep with someone else while being in a relationship...