Remus hadn't really expected Sirius to argue. After all, Sirius had expended a lot of energy trying to convince Remus to let him. Asking for it, Remus thought, would make it a done deal. Apparently, Sirius had better self-control than Remus had believed.
"I do want it," Remus admitted. "More than you know."
Honestly, Remus didn't think Sirius wanted it all on his own at all. He believed that once the baggage was resolved, Sirius would be on his way. And that was why he hadn't wanted to let Sirius snog him. That was why he was selfish. He didn't want Sirius to forget that desire. He didn't want to go back to being the only one wanting... It was easier when he wasn't alone. But stringing Sirius along just for the sake of feeling less lonely about it all... that was wrong.
"But you have to consider the possibility that I might need the baggage to be resolved before I can believe it's just you." If Sirius did stick around, by some miracle, then he would know. Or at least, come a little closer to believing it.