"burn your bridge behind you"
This expression may have originally been "burn your boat behind you.", which originated with the Romans. Roman generals, including Caesar, often did burn all their boats after invading an alien land to impress upon their legions the fact that there could be no retreat.
Later, bridges were burned for the same reason and the phrase to "burn your bridges behind you" came to mean, figuratively, to take a stand from which no withdrawal is feasible . --word origin