If definatly sounds like shes jealous and is also doing this because of your partner.
As its a hotel you have a proper personnel department, go have a chat with them, tell them that you dont want them to do anything yet though (so you can make them aware and if it does go further then at least you have made them aware early one.) Also you might want to think about moving departments, there might be openings in reception or something.
Good luck with it cos its not nice, my boss is toxic too but we have no personnel or anything like that!