My best friend talks about her all the time. [If he's scowling as he says that it surely has nothing to do with how he should be using the past tense. More importantly, there's the chance Yu's told Yosuke about the break-up and he's really not sure he wants to open that particular can of worms.]

I don't see how your relationships have anything to do with this, but Yu-san must have told you about us, huh.