Agreed, it's probably easier for one of you to learn the other's game--or better yet, for each of you to learn the other's.

For blending the two, one basic difference is that the terrain on a chessboard is all neutral, with no effect on any of the pieces, whereas the xiangqi board seems to have landscape features that affect the pieces' movement. You would need to decide whether you want the terrain to have an effect on the pieces or not, and if so, how and how much.