>>7235523 (cont.)And
>>7234996 is completely right. Towards the end of last year my two ex-best friends started giong out with other people too (always together, but still they kind of got less self-absorbed and it wasn't as heavy to spend time time with her as it was when they first got together) and they apologized. They might not be my _best_ friends anymore but we're still good and talk quite often.
In short, let the two girls sort them out, eventually they'll fix the problems they have inside their relationship and your friend will come back. But don't waste your summer. Take time to cheer up but don't waste it, and if possible engage in new activities where you can meet new people and everything will sort out in the end. Wish you the best of luck anon