It must be hard having him still in your house. I know from experience that this can make it hard for both parties to move on. Is there a way the two of you can get sometime apart? It sounds like he might be in shock right now or trying to see how much you really meant what you said. Maybe if you had some time apart it would help it become reality for him. Is there anyway you could take a little vacation...long weekend type of thing to get away? Another thing to think about might be setting a dealine for when he does have to move out, so that he gets it that he needs to start working on other arrangements.

Stick to your decision since it seems like it was what you wanted. Tell him to return the ring.