I think the guy just got old and she tired of him.
It really doesn't matter what the girl thought and did when she was fourteen years old. As soon as she spent the first night there without her parents' knowledge and permission that's a crime. The guy was an adult and she was not. I'd say a long, long stretch in prison for the guy sounds about right.
BTW - I like your screen name. They are facinating creatures. I met one once.