Meant to be

This is a story about a perfect society, a perfectionist life style. The government wanted to make sure that their world would resemble an utopian society. To do that, at birth every child would be given a necklace that were an unique shape, and your "soul mate" would have the matching one. The necklaces got warmer every time the set of "soul mates" got closer to each other, but there is a secret that the government tries so hard to hide.
This is a action, romance story.