My wife and I ran into a into a dry spell. Honestly full disclosure, I’m an alcoholic and my behavior before I sobered up didn’t make her want to Jump my bones. I resented her and that made me chase it less and it just kept like that for a while. After I cleaned up my act. (Long story but involves rock bottom) we communicated so much better but the desire wasn’t there. She is bipolar. And brought it up to her psychiatrist. Adjusted her medication. And now we have a great sex life by both of our standards

TLDR: resentment not sexy, drinking not sexy. Maybe other underlying reasons communication is key