Hi Enoughalready, I'm sorry you're having to go through this.
I was struck that both of you seem to be issuing ultimatums over this - he's saying no house or holidays if you keep it, and you're saying end of relationship if you make me get rid of it. I understand that you are going through a really difficult situation, but both stances come across as quite passive aggressive. Can you sit down and just talk to each other about it without making decisions or talking about ultimatums? This way you might be able to talk more constructively.
It's not fair for him to blame you for making a mistake. You took responsibility for contraception (and put your body at risk) for many years. The pill is not 100% foolproof. He could have taken responsibility himself, condoms, vasectomy etc...
He cannot 'make' you get rid of it, you can only decide that yourself. Will he put a lot of pressure on you if you decide to keep it? Will he leave? From what you are saying it seems he wouldn't - i.e. he's complaining about holidays and the house. Can you afford to bring up two children on your own?
You have one DD and I get that you want her to have a sibling. I would love my DS to have a sibling (sadly too bloody late). She is going to be affected by whatever happens, so you talking about her interests to your DP is the right thing to do.
Good luck, I hope you and your DP find a way through...