I'm sorry you're hurting and trying to explain why she left probably won't help you at all. Unfortunately, you've got to accept that she IS leaving. Sure, there are considerations about where to go from here with therapy, but I wouldn't necessarily focus on that just yet. She is going and that sucks for you and it really hurts. All you can do is accept this hard fact, know it's okay to feel the way you do, and eventually move on.