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it happens to lots of singles in their 30s. the priority becomes expanding the social network (new blood) with the hopeful side benefit of finding a significant other.
you're her friend, I'm sure she still cares about you. but if you're hooked up already then you're second on her priority list. She wants to see you, know you're well, but if she's afraid she's going to miss 'the one' when she's hanging with you then she's going to be late showing up.
I've seen this a LOT with both men and women... taking a probability approach to dating... meeting more people betters the odds, all while maximizing your time.
And then it ends up going the other way when she finally hooks up with her guy and your 1st priority becomes your kids.