I would talk to him about it, or draft up a new rental agreement and ask him what he thinks of it so that you can print the final document for signature. If he bulks at this, then you should seek legal assistance, or move out - because if he does not agree to take his stuff out and share in the utilities, he's using you and will probably throw you out if you move his stuff on your own, unless you talked about it earlier. I think the draft should also include a suspense date specifying the exact date that you will be able to fully use the finally emptied space you are paying for - that way if he signs it and does not take his stuff out to make room, you'll be able to move it out without repercussions. Good Luck.
