Some people like to divide, usually these people wants to use division to make them feel different from the other, feeling special it is.
In lots of cases bewteen female friendships, marriage divise between "Us" and "Them". Such idea had been explored and examined so many times but still confusing to people.
It is true that some women feel superior over their friends after they got married and had a child (children) - where they mark their "achievements" over their friends who are "behind".
Some women even distance themselves from their single friends after marriage until these friends become married too. Well... if a friend distance herself from you simply because she is now married, she's just a pig who's not your friend to begin with. An unfortunate pig who is not intelligent enough to operate on different levels and embrace the past for the future.
In case of Belle, for knowing Slow for almost a decade, but Slow getting marry can not help to make Belle to feel like Slow is dividing her life from their friendship...
Wait a minute... most people says when woman get marry they change, how about their single friends around them - don't the single woman (eg Belle) view the soon-to-be-married friend differently and cause change in behaviour and ultimately causes the big divide? Everything's a bit two-folded, isn't it?
Who's "Us"? Who's "Them"? Who's your real friend? Would you give up your friends or husband to feel "special"?