If your EX broke up with you because he/she can't decide if that's what they want, then give them their space. Leave them alone. If you run into each other, be friendly, make sure that they know that you are okay without them. Go out, do things. You don't have to date someone else, just be "unavailable". Their mind will start playing tricks on them. With any luck, it will force them to confront their own feelings, and give them the courage to fight for what they want.
This tip was submitted by an anonymous visitor to our website.