Maybe tell her you dont understand her knitting and cross stitching? No dont do that, that will just put you in the dog house. But everyone needs a hobby. My girlfriend (soon to be fiance) says I have to many and dont need more. I even told her that her and I should find one to do together that way its something both of you can do and have fun with. Not everyone can explain the understanding of all hobbies other then that there are a people who are attracted to a certain craft even though it may or may not be understood why. Maybe just simply put tell her it keeps you on the wagon and keeps your sanity and that you would also hate to lose your mind on her because she means so much to you....lol maybe that will get you points. Good luck.
