I've followed along with some of your posts on here. You've tried, you've really tried to improve things and it hasn't worked. I think you can walk away knowing in your heart that you gave it your best shot and it just wasn't a relationship that was salvageable.
You could live the rest of your life being miserable, out of a misplaced sense of obligation to other people. I say 'misplaced' because if these people really loved you they'd want you to be happy too, even if that meant leaving your marriage.
Or, you can leave and have the chance to actually be happy and independent and lead a happy and fulfilling life.
Your husband might say that he's happy and sees nothing wrong with your marriage, but surely he must sense that you're unhappy, and I can't see how anyone could truly be happy being with someone who's heart was no longer in it. If you let him go, he may have the opportunity to find someone who really wants to be with him too.
Staying together is holding both of you back from finding true happiness.
This isn't a dress rehearsal, you don't get to go back and do it again. You don't ever get this time back. So you need to do what's going to make you happy. It's YOUR life, don't live it for other people and sacrifice yourself in the process.
Best wishes hun xx