Of course, it is sad when a relationship ends—usually for one of the partners, sometimes for both. Nevertheless, it is unacceptable not to respect such a decision! Any attempts to influence or pressure the other person at this point are a criminal offense!

People change, and not always in parallel or in the same direction. That's not a bad thing; it's just life. In the case you describe, however, I would argue that the relationship was never healthy in terms of mutual trust.