Yay for J and A,
You guys are in for such a treat. Through my personal experience I have come to find that unconditional love does begin with marriage, yet it doesn't really take on its true meaning until you have a child together and that bond grows as you watch your own creation take shape, personality and unconditional love for the both of you.
Thats when you really know.
I wish you both all the best and hope nothing but happiness.