I would like to say that I am sorry for what you're going through.
"Marriages" are a lot of work. The work isn't just in trying to learn to live together. The work isn't just learning how to share lives.... the work also involves the sex and intimacy. Keeping the love, intimacy, and sex alive and a vibrant part of the relationship is hard hard work.
It sounds like while y'all were working on other aspects of the relationship, you may have not worked quite so hard on the intimacy and the love. Those are key ingredients in bonding two people and, in my opinion, the hardest things to work.
We always take the sex and intimacy for granted expecting those areas to take care of themselves when they don't.
I hope you can work it out with him. In my opinion, 11 years, is a lot of time to throw away. Even if you have grown apart, you can always work to come back together.
As someone else said, don't all marriages go through this? I think they do whether it's hetero or us.... lol
After a few years together, we often reach a level of contentment and begin to coast in the comfort of that contentment which means we begin to not work quite so hard on some areas of the relationship. I know how this goes. We went through this.
Our first 3 to 5 years were somewhat rough. We had to work so very hard not to argue, and it took us at least that long to learn to live together, share ourselves, etc. After that, we began to settle into a period that seemed peaceful and content with one another. We began to slack off. After a couple more years, we began to hit rocky times because we stopped working hard on the relationship and all aspects of it. Once we began to work on it again and once we finally began to put the other one first in everything, things really started to come together. So... for us it took about 7 to 10 years to get it to working for us both. Looking back, it seems so long ago at times and at other times, seems like yesterday. I wouldn't give back the 18 years I've had with him for anything in the world. Not only are we true partners in every sense, but we are also best friends. He is my rock.
Good luck and I hope only the best for you!
P.S. Hopefully, not everyone takes as long as we did to turn it into a "bed of roses."