Surprise answer, but you probably should hire a lawyer! :) The police are unlikely to resolve this dispute. He'll claim it is his, and they're not going to be in a position to force him to let you take the furniture back.
Call a lawyer and ask them about getting a "writ of replevin" A writ is an Old English word that essentially means "Order" A writ of replevin is an order regarding ordering the return of possession of personal property.
So here's how it works, your attorney files a replevin action and applies for a writ of repleving. Your ex is given notice and notified of his right to object to any potentional order. If he fails to object, the court will grant the order. If he objects, a hearing is held to determine whether your ex is in lawful possession of the furniture. If not, the court will grant the order.
The writ is given to the sheriff's office who then goes to your ex's property, lawfully enters the property for the sole purpose of removing the furniture and delivering it to you. If your ex interferes, he faces contempt of court.
Now, I should warn you that there's a legal distinction between possession and ownership. When you say you 100% bought and paid for it, I assume it means that it was paid for out of an account in your name only and was not bought, at the time, intending it to be a gift to him.
So, again, this is why you need to talk to a lawyer. Good luck!