How to fix my stagnant relationship?

Me and my boyfriend have been together 3 years, we have lived together for almost the whole 3 years. We get along great, we trust each other, love each other dearly. We have great communication, and we don't fight. We argue yes, and push each others buttons from time to time, which is normal. But I feel our relationship is turning into a rut. Nothing exciting, how to spice it up and get out of this rut? Also, I feel like Im always in a pissy mood. And I think it's really starting to bother him that I'm always pissy. I don't know why, how do I get out of this funk. Any advice? Thanks