I was in a similar situation. My lawyer told me that even though the guy never paid me a dime in rent I might need to go through legal eviction (which is expensive and lengthy). I admit I offered him cash to leave, which he accepted, albeit not without a struggle. Thankfully, he either never thought about getting his own legal advice, as he was too consumed by his venomous anger at me to explore his (legal) options.
I was elated beyond my power to describe when I got him (and his mountains of junk) out of my home.