I am in a similar situation, but I am the borderline

A co-worker - I should say subordinate as that is the reality of the situation, but I see her as an equal. We met four years ago, and I was immediately attracted to her. Apparently, it was mutual as people were telling me that she kept talking about me, asking questions. Even her own mom who also works there told me that she wouldn't stop talking about me. It was surreal, and at the time I was unaware I had BPD and intimacy issues. We did talk, but neither of us would make a move.
She was only there briefly and we let her go due to low hours. Not long after, she friend requested me on facebook, and we interacted occasionally through there. Nothing big. Liking each other's comments; commenting on each other's posts, and occasionally messaging. I'm borderline though. This is HUUUUUUUUUUUGE for me.
Almost a year of this and after I was diagnosed with BPD, she asked me if I had any work for her, and I personally hired her back. I honestly would have fired someone to make room, but it didn't come to that. We picked up where we left off, and were even a bit playful at times. She was quickly, and I do mean QUICKLY idealized. I developed a fantasy relationship with her all on my own in a matter of days. So at this point, everything and anything she did or said would affect me on a grand scale, which in turn freaked the living crap out of me.
I began cross training her to increase her employee value and job security. Even gave her up to other management to ensure so. We continued to talk, and I continued to fantasize and creating an image of her she could never live up to. I knew she would never make the move, so it had to be me. My massive fear of rejection and intimacy kept me from doing it. My therapist urged me to get past it. Told me to not let it devastate me if she says no, seemingly unknowing that there is nothing I can do to prevent that.
So the opportunity came, and I asked her out. To my total surprise, she said yes! I immediately messaged my therapist and told her. She knew what was coming: Me freaking the f**k out. I immediately started having anxiety that she would cancel on me. The date was five days away giving her way too much time to reconsider, or for some BS to come up, OR for me to f**k it up.
All I do know, is that she DID cancel on me. Do you want to know what this did? It completely, and totally screwed me up. I got wasted. Did plenty of drugs. Flirted with her BFF in front of her and screwed a dude. I unfriended her on FB, but not before a plethora of passive-aggressive memes CLEARLY targeted at her. Finally, I told my sister what was wrong as there was no longer hiding it, and I bawled like baby being taken away from his mom. She got the axe, and it KILLED me.... she was supposed to be...
...
Anywho, she still works there. Under different management, and my heart breaks everyday having to see her, knowing that she is with someone else. The ironic thing is she didn't see what my sister saw. She doesn't know about the drugs I took, or being wasted, and having a guy plow me. In fact she has no idea how devastated I was. All she knows is that she cancelled on me, and I acted like an @sshole and unfriending her and becoming distant and silent.
So now, her and I are just like you and this girl. We work together. Things are awkward (for me), and that fantasy I had of her has been immortalized through petrification. It'll never live, but always exist. We lock eyes from time to time, but it's just a reminder of the aforementioned.