I had this exact situation and it became much worse when I was working at a job I hated and had trouble dragging myself into at the best of times. My spouse has a very good bedtime routine and forcing myself to at least follow that along with her helped, though I still have trouble getting to sleep as easily as she does.

I don't think there is any one thing that helped me come out of it either. A few large changes, like a better job, and some moves like limiting caffeine intake after 3PM or so helped. I feel like it's stress, plus being a night owl to begin with, and maybe a light sleeper as well.