Tips on Spicing up the sex life

We have been together for 5years and I would like to spice up the sex from my side. My boyfriend would like for me to be more spontaneous instead of having him to ask. I know that it must sounds really bad that he has to ask, but in the beginning of our relationship I would get dressed up all the time but he wouldn't be in the mood, now I feel that it is safer having him ask and I'd be happy to get all dressed up for him. So since we are TTC I would like to change this and spice things up. Tips please.