I think being unique is the answer to this. you must surprise her even if its things that seem stupid such as sleeping on the other side of the bed.
Take her somewhere that neither of you have ever been. and try new things in your sex life. there are so many new things to try and if all fails then how about going for a new look and pretending that you have just met going for that first date again can be a real sparker. hope I've helped. good luck . x