A little perspective please?

To me, it sounds like he's looking for a way out of the relationship. He probably moved in because he either loved you and wanted to be with you or for some selfish reason. You can learn a lot about a person by living with them, and it is possible that he came to the conclusion that you two are not compatible or he's having the need for space to live his life. Face it, living together is like being married. If this is what he wants, it's probably for the best that something like this happens now before it's too late if marriage is down the foreseeable future. Maybe he's not ready to take the next step and wants some space.