Megan Hamilton: 2 books

The Glass is set in a post-apocalyptic world where people now live in small isolated communities, and struggle for their survival. In one particular community the people have learned to value wisdom more than knowledge, for all the knowledge in the world had not saved people from their own foolishness....

Cassandra was alone in her world. The only person she was able to count on was Adam. She thought that he would be there for her forever. When he left she was broken. Then she decided to break him too.