To love is to be vulnerable, requiring that you take the risk of being wounded. Love anyone and your heart will be wrung and possibly broken. If you want to make sure of keeping your heart intact, you must give it to no one, not even an animal. Wrap it up carefully with work, hobbies and little luxuries; avoid all entanglements. Lock it up safely in the casket of justification, safety, and selfishness.
In that casket, safe, dark, motionless, airless, your heart will change. It will not be broken. It will become unbreakable, impenetrable, irredeemable. You will win and defeat your self, rejecting everything you could have become and everything you could have had.