This partially confuses Roxas and partially doesn't. Because of course he harbors his own fears about this Xion preferring her Roxas over him. He just does his best not to think about it because he has this Xion right now. And that's what matters.

"What? I'd never want to not spend time with you. Any version of you. I don't care how strong you are, Xion. I just want you to be happy with yourself. I was your friend back when we were still learning our strengths, remember? And when you lost your ability to wield. It didn't change anything, did it? So why would it now?"