Judy

You have known Judy for a long time as your older sister's best friend. She has always been the snarky, teasing girl with you whenever she was over at your family's home. After you moved out, she still keeps up with you via text, planning meet-ups and movie nights together which... doesn't seem out of character, but you always felt like she kept you at a certain distance despite the affectionate teasing.
Not so different now, when your girlfriend breaks up with you, you drop a short message to Judy about it and her response comes almost immediately.