When I was younger I remember reading an amazing book about a man who takes his fiance/girlfriend to his home to meet his witch family. Could even be that they are married already. Something that is really sticking in my memory is that they don't fly but instead use the natural thermals of the earth to kind of ascend into the air. This could have been around 1999 that I read this book.
Any chance it could be The Thread That Binds the Bones? It's her family rather than his, but some of the magic is similar and it's a book that lingers in the memory.
This could have been around 1999 that I read this book.