Love, as an emotion, can be let go just as any other emotion.
Remember: You are not your emotions, though you can experience your emotions. Just as you can choose to let your building anger pass in stead of becoming angry, you can do the same with happiness, love, sadness, or whichever emotion you wish.
This is not necessarily the same with some things such as depression (an example), which can be a chemical imbalance rather than an emotion.
But I am curious: Do you choose not to love, as in romantically, or not to love as in any other person in general?