Dear Confused Again,
Embrace your differences, or seek more compatibility.
You seem to think that there is a right answer to your question. I don't think so. The differences that push you apart are directly dependent upon how tightly you each hold on to your own view. In other words, the stronger your views are about a particular thing that is different from his, and the stronger his views are, the less likely you will find a common ground.
If He's Born-Again, Forget It
Take religion. If he is a devout, born-again Christian who thinks that unless you are saved that he can't be with you, and you are not so devout, then you have a problem that I don't think you can solve.
On the other hand, if he is a Christian and you are Jewish and neither of you thinks that the other religion is wrong, then there is definitely room for you to be together.
What Are You Compromising?
I worry what "old fashioned" means. If he wants to put you into some kind of box that you don't want to be in, then it will be tough for both of you. I guess the question for both of you is: how much are you willing to compromise?
That's what love is, the dance of compromises...