Pesky Exes

Kristen
Does your significant other have an ex that doesn't seem to go away? No matter what they're brought into conversations or you see them driving around and that seems to be the topic for the rest of the day? How can I get this to stop?
So my boyfriend absolutely despises his ex fiancé simply because she is a horrible person. She comes up in conversation quite often but we've been able to avoid her since we've gotten together. Well the other night we were picking up our friend and she was at our friend's house and when she heard we were outside she ran out of the house and up to our car. She started telling us all about her new car, her new house, her motorcycle, yada yada yada. When she's done she's says to my boyfriend "you're going to get out and give me a hug whether you like it or not". Of course my boyfriend told her "absolutely not"  and we left. Is it okay that I'm mad that she came up to the car? Is there any way I could've prevented this or can prevent it from happening again?