You can calculate that the proton and neutron in a deuteron spend quite some time so far away from each other, that they are outside each others force range. Why doesn't the deuteron break up? Is it because of the binding energy?
The binding energy is just the energy the one would have to put into the deuteron to separate the p and n. The nuclear force is responsible for binding the p and n.
I believe the probability that the p,n in a deuteron "spending quite some time so far away from each other, such that they are outside each others force range," is exceedingly small, if not nil. If that were the case, then some deuterons would spontaneously dissociate.