Most Helpful Guy
It is unfortunate that you moved in with someone that soon. You're only 19 and you've been dating him for 8 months an moved in together? Never a good idea.
But what is done is done. I am sure you've grown closer since living together. That must make it much harder on you. However, "just wanting to be single" is his way of saying he wants to see other girls. Time to separate. Don't make the same mistake again.
Most Helpful Girl
Unfortunately, there isn't anything you can do. If he wants to be single then you can't change his mind. I don't think it necessarily means he wants to be with anyone else though. Maybe he just feels like he needs some space right now. Living together after only 8 months of dating is a lot for any relationship.