What...what break up. He says, "I'm sorry that things got so messed up between us. But whatever happens today, I want you to know how much I care about you." Basically, "Even if I flirt/go out with Korra, I still love you." In the case of "I still care about you", it doesn't come off as friendship cause, you know, THEY WENT OUT? It's exactly like the "I'm sorry, I don't like you that way but we can still be friends?" that everyone hates so much. But hey, at least there's a clear inidcation there