Hi Lilly
To answer your questions:
I am having individual counselling. It has been an enormous help to me and my frame of mind. I thought we would be focussing on my relationship, but in fact it has been more about my father. I have come to realise that the problems in our relationship are not entirely my DP’s fault – before counselling, I blamed him completely and utterly. I treated him with contempt. But this is slowly changing, and I am noticing a big difference in the way DP and I interact not counting this week as I have ‘Aunty Flo’ visiting and we are getting on again. We are sleeping in the same bed again. Things are looking more positive.
I was 1 year old when my parents officially divorced. My sister was 7. It was the best, most brave thing my mother ever did for us. I thank her every day for getting out. He was physically and emotionally abusive and controlling. He came back intermittently, and when he did, our lives went back into turmoil. She says she let him back in those times so that we wouldn’t blame her for cutting him off. She did not want us to think she kept us from him. I kind of wish she had; but I understand her reasoning, and its fine. I am working through my anger towards him through counselling.
She absolutely did the right thing by leaving him and becoming a single mother. She lived in another country to all her family and she truly was alone with us…but she did it. And she did a fantastic job. I love her so much and honestly (I know I am repeating myself here) she is my hero.
The only thing that affected me badly was when my father came back. We were so happy when it was just the three of us – calm and loving and consistent. As soon as they were together again, there were fights and arguments and crying and hurt and anger. Those were the bad times. My best friend at school also had divorced parents and it was never an issue for me. I was aware from a very, very young age that my parent’s divorce was a good thing.
Please do not feel guilty at the prospect of bringing up baby without their parents together. Really, it’s not uncommon and it’s in NO WAY a bad thing – most often it’s a bloody good thing. You do not want your child being brought up in a war zone – this will mess your DD’s head up – not divorced parents.
My mum's situation is different from yours of course. Your DP is not violent. I would assume he would have contact with your DD. And it seems to me that both parents would be a lot happier / calmer if separated – and this equals a happy baby.
I hope my drivelling has helped a bit. Obviously only you can decide what to do. I am sure you will do what is right 
If you have any other questions, please let me know.