Hi, am hoping for a little advice, on separate but related issues.
H walked out on dd and me 3.5 years ago, totally out of the blue. He left for another woman, who he is still with.
Dd lives with me, and sees him twice a week usually, one evening at my place, while I go out, and at the weekend for a swimming lesson and lunch. She has never once stayed the night at his. After a while, he gave me some money every month, but then stopped when he lost his job. Since then, I've more or less had nothing, apart from this year, he managed to give me a small amount for a few months before once again losing his job.
We had just bought a house, and only living there for 9 weeks. It was in a new town, miles away from all my friends and family, so I didn't want to stay there. We have rented the house out, but the rent doesn't cover the mortgage by a couple of hundred pounds, and he has been covering this.
I have just found out that he and the gf are expecting a baby, and it has made me really worry about the situation dd and I are in as this is going to make his financial situation even worse.
So in a nutshell, what are my options in securing maintenance for dd? I can't see the point in going through the CSA, as he has nothing to give me, but perhaps now it's time? He has debts too, and just says he can't give me anything because he has too many outgoings.
As for the house, I am desperate to now just be rid of it, as I'm worried he'll stop paying for it. It's in negative equity as we bought at a bad time (thinking it'd be fine as we'd be there for years 
) and it's safe to say I don't have the cash to make up the shortfall. If I get in touch with the bank, is there a chance they might just let us end the mortgage and write off the shortfall?
Sorry, I know these are broad questions, but I can't think straight at the moment, and can't even work out where to start with any of it. Thanks...