I wouldn't say that you were "replaced". If you and her have been BFFs since elementary school, that's awesome and there's no replacing that!
I thinks it's more like that she's found a BF and of course she wants to spend time with him.
Relationships with a BFF and relationships with a BF are both great, but each one has it's own thing!
You may want to try to make an extra effort to make time for you and her to spend together.
You may also think about getting a BF and the four of you can "double date".
Try to support her in every way and let her know that if this relationship that she's in doesn't work, then she'll always have you as a BFF, not matter what!
"The body says what words cannot."
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