longbough

Questions that remain:

Is Steve your "best" friend? Or is he just an equal friend among your group of five.

If he's your best friend of the bunch does Steve even try to explain things like, why you weren't invited? It's hard to believe he wouldn't.

If he's not your best friend then you've got to respect his privacy and his decision to marry the girl. Their relationship is really none of your business - especially if they're married. Let it be known that you're still around and still consider him a friend. Go hang out with your other friends and let him know that he can call you any time. You can't expect to be liked by everybody you meet - so let it go.

Surely you MUST have SOME idea why she doesn't like you, right?
-Maybe, before they got engaged, you commented to either Steve or another friend that you thought she was a controlling "b*tch" or a "ballbuster". If that got back to her, can you blame her?
-Maybe she found out that you and Steve spent 2 memorable months in Thailand and she sees you as part of his "past."
-Maybe it's just because Steve, historically, looked to you for advice about everything and now she sees you as competing for his trust.

No story is ever simple.