Why am I feeling like this and what can or should I do?

I use to love having with my boyfriend all the time. I would crave for him even just thinking about him. We have been together for close to five years and lately I don't feel like having with him anymore. I just do it now to please him but can't wait til its over. I don't know what to do in my situation or why I feel like this. I don't even like kissing him anymore either (I'll give him a peck just to greet him). We don't live together but we do spend the night together a lot. But when we do I just want to lay with him and snuggle. I don't mind doing that with him. It feels good to hug and snuggle with him but that's it. And I can see that he likes that too but he always wants to have and when I don't want to I can see he is frustrated and hurt.