What would you do if you develop some infection on your arm? Will you cut it off? What will you do if someone close to you walks out of your life-giving all wrong reasons? Will you become bitter with them? These decisions should be taken by ourselves. We are called adults for a reason.
We have to own our life. Others and situations are secondary. The guiding principle should come from the self.
Impermanence is the only constant. Everything else is cyclic: weather, relationship, situations.