It is hard for both of them to get along. I can tell you this
based on my first hand experience.
My bf (going to be my husband soon) also has a very close girl
friend. And he used to like her for quite some time before he met
me. We have been together for 2 years plus now, he already proposed
to me, we are getting married end of this month. But he still kept
in touch with his close friend, in fact they are even closer now
because he said he only treats her as his close friend and the girl
also only regards him as her friend.
But that doesn't stop me from being jealous and insecure once in
a while, because after all he used to really like her a lot in the
past and like what your gf said, I used to believe that given the
right time and place, they might end up together. I even had
nightmares about it. Everytime I brought this up to him, he would
say that I am thinking too much and that he and the girl is just
close friends. He even hope I would get along with her, and that's
why I have been making an effort to talk to her, etc.
But it doesn't change the fact that it is kinda awkward whenever
we chat, I am not sure if she feels it, but I am definitely feeling
it. You can say that I am thinking too much or whatever, but I
don't think it is possible to become close friend with your SO's
ex-crush or girlfriend.
So please don't pressure your girlfriend too much into doing
this. It is good enough that she can be civil to A. Just let it go
at that, I think it is very hard for them to become chummy chummy
with each other. And meanwhile, you should start spending more time
with your girlfriend, and more reassurance will be needed. And
don't tell your gf that she is being paranoid, don't tell me you
won't feel that way if she got a best boyfriend whom she is very
close with and talks to him all the time.
Just put yourself in her shoes.
Honestly, I do have some close girl-friends who are like A,B or
whatever letters.
From a mutual point of view, the romance part between me and the
letters have long disappeared because we know each other for a long
long time. It's not to the extend of hanging out every other week,
but maybe meet for dinner once a while?
and it didn't help when I spent 98% of my time with my ex and
she still gets jealous. it was to the extend where I never msg my
friends, never go out with them, all day with her, and when my
friends randomly msg me, it became my fault.
But that has past. I think I am not myself anymore which is not
the way. I have my guy buddies too and I hang out with them too
often she also jealous, say my guy buddy should get himself a gf
and such..
Sometimes the guy has locked his heart for you but you keep
squeezing it. Until he can't breathe. One fine day it'll all be
gone. He'll just unlock his heart and open himself again.