Know that whatever you say is likely what they’ll fixate on after the breakup because of something called the narrative fallacy. Our brain tries to create a cause-and-effect story to explain the events we witness and experience, even when that story is false. Any breakup is likely a response to a whole number of situations and dynamics, but when you end things with someone and give a specific reason for doing it, they’ll obsess over that reason. Don’t plant that unhelpful seed in their mind.