Clearly your W is already breaking the agreement you came up with. You need to put your foot down and tell her that she isn't coming. Caving into the first thing will lead to you caving into other stuff. Might make you seem like an a**, but your W is putting you in this situation. And by giving in you will lose respect. You may have insist on making her parents time at the home very uncomfortable if they show up. Being passive will not get you any points. It's just going to get you a house full of people against you.
