My mum stayed with my dad because she had children and she 'didn't want us to grow up without a father'. My father was an alcoholic, my mother was resentful and unhappy, they were always rowing, he would get blind drunk, she would leave us with him. She was, or became, very controlling as she felt like she had sacrificed her life for us. She told me (I am her second child) that she felt like her first child had been a mistake, but her second was the millstone which meant she couldn't leave. She felt trapped. She was emotionally neglectful and abusive. She told me my father screwed her up. Etc etc etc.
I'm still untangling the results.
Was it the right thing for them to do? I am really not sure. My mother had so many of her own issues, I think she is fairly toxic (was she always like that?) that I do wonder if she would have just transferred her rage about life from my father to us, had they separated, or whether she would have had a chance to work it out - but she didn't want me, so not sure it would have been better. I think the fact that she said she stayed together for us (children) was just a way of blaming us for her life (which worked, I felt guilty for years for existing).
Personally, I think you should not have another child until the issues are sorted, if they can be sorted, why would you have a child with someone who has a drink problem, is EA/VA? The child will think it is their fault their father cannot stand to be sober in their family (well, that is what I thought).
Sorry, I know that is very negative. Neither of my parents would have gone to counselling, for a start, I did suggest it at one point (cue verbal abuse). I think they deserve each other really, so the question is do you deserve your H or do you deserve better? What does your DD deserve?