I left my husband (together 15 years) two years ago due to figuring out I was much more attracted to women than I was to men, and therefore our long term sexual incompatibility likely wasn’t solvable, among other implications.
I’m not 100% only attracted to women, but I definitely lean that direction. We had enjoyable sex a substantially more frequently than you are.
But what matters isn’t what’s normal in someone else’s relationship - once every couple months will be perfect for some folks and totally untenable in another. The trick is to find someone who’s loosely on the same page. Also, IMO, quality and other forms of sexual compatibility matter quite a bit as well.