Lyric discussion by moik 

Cover art for The Right Thing To Do lyrics by Carly Simon

The statement "Lovin' you's the right thing to do" implies that there is a moral decision being made here. If "Lovin' you's the right thing to do" is one choice then "Lovin' you's the wrong thing to do" is an implied alternative choice.

But why would it be wrong to love somebody - isn't that always a good thing? And is it actually a choice, I mean, you don't really choose to love somebody, do you? Either you do or you don't.

Hey wait a minute - maybe "love" doesn't mean "love" at all in the context of this song - maybe it is a euphemism for (casual) sex. Ah hah! Why that shameless hussy! Just another song about "doing it."