It's simple psychology: no contact works because it restores balance between you and your ex. Here's an example to make it clearer: when your ex walks away, your relationship is in a state of ultimate imbalance. You want the relationship, they don't - they're the ones who left. You miss them a lot, they may miss you a bit, but remember - they left. You're emotionally invested, they're not. You might even be chasing them - while they run away.
The moment you initiate no contact, the balance begins to restore. Neither of you is chasing the other. Objectively, you appear to be on equal footing. This equal footing forms the foundation upon which attraction between you two can start to grow again. This is THE REASON why it grows.
The challenge here is that attraction is a subjective thing. It exists in your - and their - minds. For the objective reality - that you're not chasing them - to change their perception, to alter their subjective viewpoint of you, we need a little time. But it will work. Time is on your side.
Now, this might be a lot to digest. But if you grasp these principles, you'll save yourself a lot of time, stress, and money. There's no need for expensive coaching sessions if you understand the fundamentals - why no contact works. And to save you even more time, and to check if your no contact is done correctly, be sure to download my "No Contact: Quickstart Guide":