I think I may have bi polar and I was wondering if that could be connected to my very poor choice in men?
My first relationship at 16 was with a violent and unpredictable guy of the same age and stupidly I got pregnant by him and we lived together for 2 years.. (although I obviously don't regret having my daughter now)
I broke up with him for my daughters sake, wanting a better future but instead I then went from one disaster relationship to the next, had a lot of one night stands to the point that the police thought that my house was a brothel.
Wanting again to break free and do better, I found a guy I was totally mad about and stopped behaving in a way that was beneath me and degrading.
Only months in to realise my new partner was a chronic alcoholic, possibly the most difficult man I've ever encountered, and we until this point have been together on and off for 4 years, have a young daughter together and live together.
He lies, steals, has been to prison twice and is going back again soon.
He has hit me and fought with me, smashed the house up, even his own daughters things, all down to this alcohol problem, drink consumes his days. He can't hold down a job and is constantly thinking of where his next drink will come from at the expense of me and the girls.
I truly thought I loved him, and he proposed to me many times but I always said no.
We are at the point now that social services are involved as they think he is a threat to me and my girls..
I feel very alone in this, and don't know if I have the strength again to face the future.
I wonder if this is what my whole life will be like?

I don't know if its down to my bi polar or whether its low sel-festeem or just the way things are. But I don't know how to get out of it or get over it?

It doesn't help that he can turn on the charm to other people and tell them that I am the crazy one! N that I in fact attack him, when it is the other way round.
When I have broken up with him in the past he has smashed my windows and broke into my house, stole from me and then moved in with my dad who is also an alcoholic!
They were at one point both seeing the same woman. To add insult to injury.
In all honesty, my heart is broken, I can't be on my own for long without pining for him as ridiculous as it sounds.
Being on my own terrifies me and I don't know why, and people say it will get better, but it doesn't it gets worse..
I can't take hearing the rumours or knowing that he is out having a good time while I'm at home with the kids struggling to get by without any csa from either father.

Any advice would be so much appreciated, I feel completely lost

Your problem is that you can't be happy by yourself. You think you need a man to validate who you are but you don't. This is why you jump from man to man and settle for anything--which isn't good for your girls to see.

You shouldn't look for the one who completes, you need to be complete first, then look for the one who loves you completely.

Maybe counseling is in order so he or she can help you face and overcome the issues you have. I hope every works out with child protective services but you brought this on yourself. All I say is OMG to the cops thinking you ran a brothel--you must had a lot of guys in and off which only put your kids in danger because you didn't know those guys.

Hopefully you get all the help you need because, not to sound harsh, you need it.

Making poor choices is something that many people succumb to and I do not think being bi polar is the reason.

As Liz above has suggested ,you can't expect men to make you happy or complete you in anyway.shape or form.
If you are healthy emotionally and feel secure within yourself you will draw healthy people to you.

Work on being alone and learn how to be happy by yourself,it is only then that you will be able to have a quality relationship.