This seems to be a point of confusion for many people: in the standard dances, the moving foot does not bear body weight while it is moving.
It doesn't even really support the weight of it's own leg. There might be a little pressure to help you feel where it is, but it's not some kind of extra prop to help with your balance.
We are generally cautioned not to lift the moving foot visibly off the floor in the swing dances, because that looks sloppy and unecessarily distrubs the body balance.
But merely keeping it on the floor does not in any way imply that it should be supporting any body weight.
Some people desire to briefly use two supporting legs during the time when they are actually transfering their weight - a time at which both feet should be stationary on the floor. I personally prefer not to pass through such a split weight time, but I still have a substantial period with both feet stationary. However, what is important and universal for every skilled dancers is that the only time at which both feet might be bearing weight would be when they are 1) stationary and 2) a weight transfer is occuring. Otherwise it's one standing foot at at time.
Think about that for a while, and you will realize why dancers much spend a good fraction of their time being technically off balance. Skilled dancers of course never let being off balance take them somewhere they didn't want to go or at a rate faster than they wanted to go... in short, they aim their movement with care.
