The guy
This is an original approach to meeting someone that we have not yet seen before in our lifetime. This guy thinks that breaking up with someone before a relationship even starts means they can have a relationship. We are quite confused about the logic and reasoning behind this, but we will entertain the thought.
So she does not know who he is but he claims that they will be breaking up. Seems like everything is already sorted out and there is no need for them to try and be together in the first place. Maybe next time he should try a different line when messaging strangers.