Exgirlfriends that need to GO AWAY!

[maggieaxid]

Ok, I have a little bit of a problem. My boyfriend (we'll call him Paul) and i have been dating for about 9 mos. and we just moved in together. And everything normally is really good between us.
however, he has this exgirlfriend (we'll call her kim) who just can't seem to let go. Now, she lives in the same town we do, knows we live together, we run into her everyonce in awhile and I am always cordial, i say hi, i don't hang on paul, i don't do anything that would make her or myself or my boyfriend overly uncomfortable.
but this weekend we saw her a bunch of times and she was sooo rude to me! my boyfriend and i would be talking and she would run up and put herself between the two of us, continuelly call him, and i would say hi to her or something and she would turn her back on me or give me a dirty look or mumble "bitch" or "slut" under her breath.i told my boyfriend this and he said to just let it go and chalk it up to her being immature and obnoxious. but he never says anything to her about it and now i am getting really pissed off.
so would it be wrong for me to confront her next time i saw her?