Most Helpful Guy
I'd tell her. And follow up with if they show up again, the police will get a call about being harassed by an ex. What was she thinking - going to some woman's house to see a cat? And she didn't have any clue you were his ex? Not buying that at all.
Most Helpful Girl
Tell them you'll call the cops the next time they come around.
If you don't want to do this...
Simply don't react to them coming by your home.
Don't open the door.
Don't show you are upset.
The more you react the more you will make them happy (because they want you to experience those emotions).
Don't give them the satisfaction