I am a newb but I'll try. I think you should wear a white shirt. If you wear an off-white shirt, you risk looking in your pictures that you are wearing a dull or gray shirt. Even tho you are wearing a suit and not a tux, black tux and white shirt are the classic combo. Also, you will look better if you don't wear a black tie. More experienced members may chime in with better reasons.
Best wishes on your upcoming marriage!