The ex-girlfriend keeps sending harassing text messages to get back together.

If he sends messages every day, just ignore him, so he will think that you have really forgotten him and have no love for him.

In fact, his psychology is just a dependence on feelings. He is not used to the adjustment period of being apart from you. If you ignore him during this time, he will get used to it. Emotionally, he no longer depends on you and will feel that his love is very humble.

Time can actually change him slowly, so don't worry.