That is a very dangerous situation. One snap of your Yorkie's neck whether it's in play or serious can kill him.
Those two cannot be together - ever. I wouldn't depend on trying to keep them apart because one slip up could mean death for your Yorkie. It's unrealistic to think that no one will ever forget and let them be together.
Sadly, for the safety of your Yorkie, you need to either find him a new home or find yourself a new roommate unless your roommate is willing to give her dog up.
BTW, what breed is your roommate's dog? |