Sorry, but what do you mean he won't have it "any other way"? Not that I don't think you should take his opinion into consideration, but it's still your choice. Are you working? If not, is his salary good enough to support 4 people? I'm sure by now you know how much one child costs, and adding another one isn't going to lessen the load. How do you plan on paying for your schooling? Do you have any support from either of your parents? Are you the one staying home to look after your baby? Is it in your best interest to add another child to your family? Will they both suffer because of financial problems?
If I were in your position, I would find the idea of having another baby completely overwhelming. You don't have to put your life on hold, and I think you would be better off getting your education and then having another child. If you're completely set against abortion, how about adoption?