You don’t need his answer. You can give him your answer: that this isn’t a relationship for you. Bye.

No one leaves relationships in order to work on relationships. Please don’t buy it. People who say this nonsense don’t really want to be with you but don’t want confrontation so they tell you stories.

Be done. Don’t put up with this. And if you really believe he left you to go to his sister to work on your relationship, go knock on her door, see if he’s there. He is not

It’s sad how much women are willing to put up with. You don’t need this bozo