I read recently a quote that said "I decided that you growing up in two happy houses was better then one unhappy house" .. It was about how a parent told their kid years later why they divorced. I think that is something to really think about.

I also think you could say you are getting emotional and mental abuse from your wife and how she is lashing out at you. And really there's no reason to stay there, even if you think it means your kid will be happier.. Because they won't be. You already mentioned she's starting to get irritated with your daughter's actions... And it's probably only going to get worse the more your daughter learns/speaks/moves around and gets into more.

Your wife might feel "burnt out" ..I am sure there's a medical explanation about new parents who feel overwhelmed and get burnt out from it.. And that could be making her overreact to things. As I am not a parent I don't know really. Not sure if it's worth trying to see if she can get a "break" from it.. Just send her away for a few weeks on a retreat and see if it changes. But honestly for your own sake as well, you don't deserve another 15-20 years of this. You are worth more then this. And if you split and get another place, at least your kid can get a happy house. It will always be about what you make it.. And if you know you will need to make it a happy house you will.

My parents didn't get divorced when I was growing up and it was definitely one of those situations where they stayed together because they wanted us kids to be happier. But it didn't really help with the horrible heated arguments they had non stop that the whole neighborhood block could hear.. And that's just part of it. It was brutal and all us kids to this day are still trying to forgive the past and haunted childhood memories. As adults now, I don't think myself or any of siblings would say they should have stayed together and that we would have probably been happier and better off in two homes. My mom was the problem in a lot of it, and she acted way worse then your wife sounds.. But I saw how much it tore my family apart, especially my Dad.. Still to this day. I believe my Mom was never ready to be a Mom, she has a personality and way about her.