As a Public Service Announcement, I'd venture to guess that all of us are saying the same thing that HWG stated.
The underlying current is that not doing anything is the wrong thing to be doing, and modeling for your kiddo.
But I still am reading you want out, rather than you want to fix. I think that is the last thing anyone should want. Watch Fireproof, get the book that goes with it, Fireproof Your Marriage. Find ways to connect. Push all-in, wholeheartedly. Leave nothing on the table. I'd say you owe it to your daughter.
Then, IF the time comes to walk away, you'll leave knowing you did all you could to give her the family life that she deserves most. You'll walk away feeling you've accomplished something, even if that something hurts your heart more than anything in the world. You'll be able to look your daughter in the eyes on some distant date, and say you did everything you could, but it wasn't meant to be, and you're sorry. But that you'll always love her just as much as you love her now. You'll walk away with your head high. If you could do that now, you wouldn't be checking in with some anonymous strangers on the internet.
Audaces fortuna iuvat.
The meaning of life is Happiness. What makes you happy? - Dalai Lama
For a more peaceful life, live the serenity prayer.