Is it a big deal if I don't invite my girlfriend to go to my hometown when I go there?

Ok so I occasionally go back to home town(in a different state) mostly to hang out with my friends. I go back about once every 1.5 to 2 months. I moved to my gf's home state to be with her and I usually spend every weekend with her. Occasionally I will spend time with her and her friends as well since I don't really have too many friends here (she usually invites me to go with her, but sometimes I'll stay in so I don't smother her). Since most of my friends are in my home state, I use that time to hang out with them. My gf gets offended that I almost never invite her to go with me. We have been together for more than 4 years and its really starting to become an issue now. Am I wrong for not inviting her?