Treat each other with care. This is an incredibly scary time for both of you. Early on, when Bill fell, my initial reaction was fear and I would yell at him - "didn't he know that (x) would cause him to fall? What in the world was he thinking?!" He finally had the courage to say to me - after he'd fallen and cracked the tile soap dish with his head (it's a great story!) - "I didn't start out to fall, it's not my intention to scare you, but you can't just start out by yelling at me!"
We both shed a lot of tears that evening, but I quickly adopted a personal rule and in spite of my terror, I didn't approach him with anger. More than once, I'd laugh, sit down beside him, check for blood/broken parts, make a smartass comment about the situation ('hmmm...lucky for us you're in the advanced ballet class now!" or "3rd grade gymnastics has really come in handy"), take a breath and then ask if he had any thoughts on how to get him upright/safe again. He usually did...and we managed pretty well! I treasure those moments the most today...my eyeballs are leaking as I type!