What do I do?...

I am posting this anonymously, so I won't be replying to any comments. Please, don't judge or be mean. I'm not here for that;

My fiance and I both have a four year old little girl together. I have always been the one to everything for her, my fiance and the house and he never really did anything. I didn't mind, as I loved being a mum and doing everything I could for my little girl. Approx a year ago everything came crashing down around me. I fell pregnant again and I had to be weaned off an anti depressant in order for my baby to grow healthily. This impacted on my mental health massively and eventually things got worse. I lost the baby quite far into the pregnancy and it caused me to have quite a severe mental breakdown. I have never asked my fiance for much, but this time I told him I needed a break and could he take over with the house and our daughter until I get a bit better. He gave me approx 8 weeks and then decided he had had enough and gave our daughter to social services who then went on to live with his mother. I still see her as much as I like and I get on well with the family; but I feel so let down and betrayed by him. He did nothing for our little girl when she was here and when he has to step up for once he sends her away and makes me feel like I've lost a huge part of me. My little girl was my best friend. She went everywhere with me and now I don't even feel like she is mine anymore. What gets to me aswell, is the fact that he has never said I'm a good mum or supported me as a mother to our child. My child was taken because I had a break down. I needed help and he refused to support me. I know all this seems a bit vague, but I really don't want to go into too much detail as it has been a really shit time for me. I just feel like I can't be here without her. I was her mum and I loved that, now I feel like I am nothing and I always sit wondering where I went wrong?

I'm sorry to ask you guys, but what do I do?

Can any of you guys tell me why he has done this?