It sounds like she is very involved with those two.

I know sometimes friendships fade when a person gets married, and his/her husband becomes the whole world. But she didn't marry them.

Or maybe she did. Well, not officially. Too bad she won't tell you. It would have been nice to include you in her new thing.

All I could advise you, be patient. Perhaps it's just a brief fascination that will pass, and she will give you the equal time, that your long time friendship deserves.

It's not nice, at all, though. Some people don't have a good friendship-needs-maintenance awareness. I know I was like that. Just following my new interests with no thought to feelings of neglected friends and then wonder, years laters, where have they all gone?