Board Thread:News and Announcements/@comment-66.60.226.250-20150416160045/@comment-6697950-20150416161800

Technically, at one point of the story, due to an accident, Kirito loses his ability to do anything. Since Asuna was not yet in Underworld, someone needed to take care of Kirito so that he wouldn't die of starvation and things like that. Thus, Alice took it upon herself to take care of him. And she usually has him sleep in the same bed.

Oh, and in case you're referring to a certain harem side story, you should know that it's not canon so far.

P.S. Please put your questions in the Q&A board, not the news board. We see such questions all the time, so it doesn't even count as "new", let alone being an announcement.