This might be long, I'm sorry. I'm not really looking for anything from this thread other than to get out everything that I need to. I don't have anyone unbiased to talk to in RL.
DP of 9 years and I split up 3 months ago. It was my decision to leave after what I perceive to be a couple of years of unhappiness. We have a 3 year old daughter.
For 3 months now he has behaved awfully. He has always been emotionally abusive, but the last 3 months of incessant abuse has been like torture.
He has called me every name under the sun. I'm evil, I'm twisted, I'm a sick c**t. He tells me that I'm an awful mother, that I'm too selfish to keep her (because I left and broke up the family). He will tell me one minute that he worships the ground I walk on, that he wants to marry me etc. The next he will be telling me I'm a disgusting bitch. He tells me that he feels sorry for me as no-one will ever love me like he does. No man will ever love all my flaws like he does.
He says he feels sorry for me as I'm fucking my life up - one day when DD decides she wants to live with him and I'm all alone, I'll realise what a big mistake I've made. He thinks she WILL eventually want to live with him. He's probably right. He lets her get away with murder, buys her toys everytime he sees her. He feeds her crap all the time, whenever she wants sweets/biscuits he says yes. Of course when she comes home I'm the horrible Mummy who doesn't let her do those things. She has been coming out with little snippets such as "Daddy doesn't want this" which worries me that he is trying to manipulate her too. 
I had severe PND and PTSD after the birth of my daughter. He's thrown that back in my face. "You weren't capable of looking after her when she was born, and you aren't now" "You didn't even want her when she was born" (Although I had PND and had some initial bonding issues, I looked after DD on my own for most of the time when she was little, she has always been loved and well cared for. I sought all kinds of help to get better and I'm recovered now).
He has threatened a couple of times to seek full custody of DD (he won't) and has said he will do anything to get it (i.e. threatening to drag up PND/PTSD and other mental health issues from my past). I don't actually believe for one minute he would get this but it's really upsetting. From the start I have suggested 50/50 care, but this isn't enough for him.
He says and does awful things, but says that it's my fault because the only reason he is doing it is that he is so in love with me. He is heartbroken and doesn't know how to handle it.
We very briefly got back together for a few days about a month ago. It didn't work as he lied about so much and behaved badly throught that week.
I have slept with someone else since we have been apart (a distraction I guess, only twice). When we got back together he told me that he knew I'd done something, if I told him honestly then he would move on. I told him. He went ballistic, telling me I was a slag, I was disgusting. He didn't know if he could ever forgive me. He told all of my family including Mum and Dad that I'd "fucked someone else" as if I'd cheated on him.
He told me at the time he'd taken a girl from work on a date, but hadn't done anything "because that's the difference between us, you dirty bitch. I wouldn't do that". I was so confused and upset I begged him to forgive me and give us a second chance. He finally caved in and agreed, and I slept over with him for the night. He said he wanted to have sex to see if he could still feel the same way about me after what I'd done. I agreed, but felt awful. I thought he would throw me out straight after (he didn't). The next morning I noticed scratch marks on his back (not made by me). He come up with some lame excuse and I swallowed it. Anyway, long story short, a few days later he admitted that he had slept with her. The woman who he told me "was gorgeous, has the body of an 18 year old" who was chasing him for months. He had humiliated me when he had done the same thing.
I've since found out that he was texting her and giving her lifts to work while we were together, knowing that she was majorly into him. He has also slept with a second woman since we've been apart. When confronted, he says it's none of my business what he does. Later on he tells me that it's not true, that he only said he has slept with someone else to make me feel less guilty for what I did? 
He lies about everything. I don't know what to believe any more.
During this time, he kept going on and on and on about the other guy. He made me give him every tiny detail. I told him I didn't really enjoy it (not true but I couldn't tell the truth). He kept insisting that it was rape. I kept telling him that it wasn't AT ALL, that I wasn't going to call it that. (I have been raped and sexually assaulted in the past). When I asked him why he was so keen on me to call it rape, he said that it made him feel better to think I'd been raped than actually sleeping with someone. After everything I've been through.
Two weeks ago he wanted to talk to me in the car after work. I agreed (i've been trying as hard as I can to keep things as civil as possible for DD, always smoothing things over). He told me that he thought he had cancer. (He doesn't).
Since we split up (the second time, a month ago) things have escalated. I'm worried he is actually losing it. For the first time ever I believe he is more than capable of physical violence and I'm scared to be alone with him. He has told me a couple of times that he wants to kill me. I know they might be shallow threats but I'm starting to worry that it might happen.
The last time we were alone together he pushed me really hard across the room 3 times. He grabbed me by the throat. He held his fist to my face, and really aggresively put his face in my face.
A couple of weeks ago he asked to meet again after work in the car. This time he snatched my phone from me, locked the doors and sped off. He said I "should put the seatbelt on, it's the only thing that will save your face". He drove around really erratically, telling me we were going to "die together". I was trying to get my phone back, he was shoving me around. I was so scared I was screaming. It was only when I finally managed to get my phone and start calling someone he pulled over. I got out and he drove off saying "see you at my funeral".
A few days later he told me he was going to commit suicide. He disappeared for a whole night. Not before calling me at midnight saying "I hope you realise that this is all your fault, and you will have to explain it to DD when she's older. I hope you can live with yourself".
A few days after that he told me that 2 years ago he was attacked when he was working nights and sexually assaulted by a group of men. He has sought councelling from the doctors and they told him that he needs to sort the relationship issues out first. I told him that I'd be there for him but I can't get into a relationship. I feel so guilty as I've been through it. He says that "any decent human being would be there". Saying how he is pathetic he is for letting it happen, and how could I "dump him after what he'd told me, I must be heartless" etc.
All the while I have texts telling me how amazing and wonderful I am. He wants us to be a family. But I must not forget that if I don't come back to him I'm a c**t.
He is not eating anything. He tells me he can't keep any food down, that he's sicking up blood. He is taking 2 packs of painkillers a day. Smoking 60+ fags a day and drinking. He keeps telling me that "it won't be long". He's trying to slowly kill himself. His family and friends are not very supportive. Most of the family are alcoholics and his friends are mostly single dad's who have been "wronged" by the women in their lives. Although I'm still paying all his bills, I've cancelled some of them and now he's saying he is worried as he has no money. As much as I hate him, I still care very much and this is breaking me. I hate to see him so low which is why I'm being drawn in time and time again.
I've tried desperately to keep things as civil as possible for DD. I wanted her to have a stable upbringing, without all the "Dad hates Mum/Mum hates Dad" crap. I've taken and taken everything he has said and done without retaliating. Everything he does I forgive for her sake.
Now he has barely seen her at all in the past 3 weeks as he is so wrapped up in himself and his mission to kill himself. He is actually making himself ill. I can't bear this any more. He harrasses me at work, then tells me he is going to die and disappears for days so I'm worried. I'm stressed up to the eyeballs. I just don't know what to do.
Worst of all there is a niggling feeling in the back of my head that I've made the wrong decision and that I have fucked up. If I hadn't have left this wouldn't have happened.
Sorry.