How do you know when you are in danger from breaking off a relationship?

You are most likely in danger if the person you are leaving has anger issues, has pushed you around, verbally abused you, has tried to control you and so on. If you notice the person waiting outside your home or work, or otherwise stalking you, seek advice and help. If it does appear that someone is following you, drive to a well-lighted, populated place ( a police station is good!) until you know they are not near.