Simple question - but lots of complicated answers. Were things hotter than a peppered sprout in the beginning? Seems like passion waxes and wanes over time - if that's what really important to you then you should move on. Love tends to endure - I think - and if you truly love your partner deeply, then leaving for a better, hotter sex life might turn out to be disappointing in the long run. ????

I stayed 10 years because of debt and the kids. Wish I would have left sooner. By sexless I mean the last 5 were completely sexless and the 5 prior it was only 3-4 times total. I also received no physical affection like hugs, handholding, etc. That might have made a difference for me. Also no emotional support.

We did try marriage counseling and I had a heart to heart with him twice but things only changed for a few months before they went right back. He also refused to talk about sex

27 years after no sex, 33 years total. I thought we loved deeply, just no sex....wrong again! Taking care of my needs myself, because of things in my history, was perfectly fine....but then he (who insisted on the no sex, not me) cheated. A lot.
Now I get a nice alimony check every week for the rest of my life, and enjoy life tremendously

Sexless relationships when you want sex with your partner doesn't is not a relationship to stay in. On the larger issue, ANY reason is a good enough reason to leave a relationship. On the point of 'for the kids' though, I can understand and respect that to the extent that it's not dangerous to stay. But being miserable is a pretty bad way to model relationships to kids. No kids=just get out as quickly as possible if that's what you want.

Too long no matter the time frame. That is a symptom of greater problems.

Let it go , if you're not happy , you're not going to want to make your partner happy . If neither of you are happy , how can you have happy children ?