@JamesColeman and thechessdreamer That's a good idea. But sometimes he goes h3 instead of 0-0, I'm trying to find a line that goes with both 0-0 and h3.
@nimzomalaysian The thing is, after Bxh6 my king is exposed.
@Telestu That's a good idea, but he usually puts heavy pressure on my knight's pin and sometimes I end up down a piece.
Black's position is completely sound after White has pinned Black's KN, but avoiding K-side castling might be more comfortable for Black and, especially if White castles first on the K-side, gives Black better winning chances. [He may be able to start a pawn storm on the K-side].
I have never really understood why anyone asks this kind of question. You can get good answers more quickly from chess.com's own on-line database! And if moves without commentary don't make sense then a good book or video on the opening is a better way to learn.