Charmed,
i really feel for you, as has been pointed out to you no one can tell you what they think you should do or what the answer is as only you know that. It sounds like you partner is dealing with it the best he can under the circumstances. He might be scared of what your dad might say given he is so strict.
I can relate well to this, I have been with my bf for 4 1/2 years and we have had a somewhat rocky relationship. We met on a blind date, I met his parents after one week, he met mine after 3 living together after 4 and been together ever since. When we decided to move in together I rang both my parents and asked their permission and I was only 20 mum said no prob. Dad on the other hand wasnt as convinced I should be committing the one sin he thought he had raised me not to do.
You have been with this gut for four years that should prove to your dad that you really care about each other. There comes a time when you have to think what is in the best interest for yourself, even being 20 you still know what you want out of life and for yourself. By the way my dad said he wouldnt pay for college either, but he came round. Once he gets used to the idea im sure he will forgive you and embrace this miracle for the true miracle that it really is.
My advice to you is this is to sit down with your bf and discuss how much hard work having a child is, find out whether this is what he wants, find out if this is what you want and once you have the answers to those questions everything else will come round.
Good luck with everything and im thinking of you in this time of need
from some one who cant wait to have a jelly bean all of their own