Reading your post, I think you already know what you're going to do. You have stated that you want the baby, you have spoken to your DP and know his position on it, and you've got a back-up plan with your family. I think you're just a bit scared and uncertain - which is understandable - but trust your gut and keep this baby if that's what you really want.
There is never a perfect time to have a baby. You'll never be 100% ready. How would you feel if your partner convinced you to have another abortion and then you break up or realize 5 years from now that he's never going to be ok with having kids? You'll have paid a huge price for him to get his way. It takes two people to make a baby, if you've fallen pregnant twice then he's clearly not trying very hard to prevent it.