What is ex boyfriend changed his number?

It is difficult to provide specific information without more context about the situation. However, here are some general things to consider when an ex-boyfriend changes his phone number:

1. He may be trying to distance himself from the relationship and move on.
2. He may be experiencing unwanted contact from the other person and changing his number to avoid it.
3. It may not necessarily be related to the relationship and could be due to other personal reasons.
4. It can be a sign of maturity and respecting boundaries if he is making efforts to create space between himself and his ex.

Ultimately, it is important to respect his decision to change his number and not try to contact him through other means if he has indicated a desire to be left alone.