<human>: Can you summarize the given text in a few sentences?

So, I've found myself in a rather odd situation. My new BF has, over a period of a couple weeks, revealed the background to their best friendship. 

They met 3-4 years ago, dated for 9 months, broke up and remained best of friends. I'm not a jealous/vindictive bitch (or at least try REALLY HARD not to be!). I definitely DO NOT want to get in the way of their friendship, or come across like a threat to this other lady.

Now that i'm soon going to meet her, I want to put my best foot forward and hopefully, if not befriend her, AT LEAST make things as pleasant and friendly as possible. I don't want to make my SO feel awkward either. And perhaps I'm a little selfish, I know that if she doesn't like me, i'll be the first to get kicked out.

How do I befriend my boyfriend's 'female best friend who happens to be an ex'? Is such a feat even possible? I keep thinking back to the movie My Best Friend's Wedding...

Please help! Surely i'm not alone in this situation?!
<bot>: SO is best friends with his ex, I don't want her to hate me when she meets me, how do I befriend her?