The purpose of an alliance is not simply for the sake of preventing an enemy from attacking you. Rather, importance lies in what one can obtain after the alliance. As well as your actions after the alliance.
Donato has to keep proving himself. He wants to prove just how valuable he is. Isn't that the case with you as well? Because you are the same as Donato. All you're doing is indulging in this twisted self-value that you have to yourself. And if you don't, you won't last. Eventually, you will break and become useless. Once that happens, you'll break and become discarded.