Breaking a habit is like losing a habit. For example, if someone has the bad habit of biting on their nails, then they could find ways to, "break," or lose the habit. If the habit is caused by stress, then they could chew gum when they feel stressed since it's proven that chewing gum helps relieve stress.
Ex:
Her nail-biting problem caused her to not have enough nail length to get a manicure with her friends. She's determined to break the habit so she could finally have fun with her best friends.
I hope this helps!