¯\_(ツ)_/¯ and so what? That person lived there, they would have had to live somewhere. They would have paid rent. You are falling into some kind of trap of thinking that life is fair that a relationship should include some kind of tit-for-tat accounting and that you should always be able to recover sunk costs. Life is not like that and neither are relationships. If you are ever involved with someone that approaches their relationships like this you should get out long before you ever move in together. If you are a person like this, just stay single and date.