How about you go over there, and say, "Gee, Suzie(or whatever her name is), I was in the neighborhood and thought I'd stop by. Wanna step out for an ice cream sundae (or treat of your choice) with me?" It'll put her on the spot, but it sounds like she needs to be, and he (evil boyfriend) might feel obligated to say "Oh, go ahead" to not look like a bad guy. Just an idea ...