Why is he trying to act as if he is ending things with me?

[Anonymous]

After a very rocky and intense relationship. I told him I didn't want to get married due to his immature and disrespectful behaviour.

I deleted everything and just stopped communicating. I didn't block him because I didn't feel the need.

Then he messages me claiming he will always love me and will work on himself and that we will be married when he is ready.

I let him know I have no intention of waiting for him.

He said he will block me for our mutual benefit until he returns.

What is this even called? Should I change my phone number?

[SomewhereElse]

I have no idea what this is called officially (if it has a name), but I think he's trying to do the no-contact rule with you. He'll probably take a few weeks / months to "improve" himself (i. e. create an excellent online impression that he's really improving his life / himself and having the best time ever doing so). Who knows, maybe he even will actually work on improving himself, but most of the time people do it to create the sense that their ex is missing out on the great new life they created for themselves.

I don't think it matters if you change your number or not. If you were serious enough to consider marriage, he's probably quite connected to your life in other ways already. One way or another, he will probably be back eventually, trying to convince you he's a changed and improved man. You could always just block his number too?