The best thing about my relationship with my exuBPD was that I realized I was lovable after all

That a gorgeous fun woman did want me and even if this didn't work out, I knew I was desirable and lovable after all!
The saddest thing from the breakup if realizing this wasn't actually true. The whole thing was not what I thought it was.
We began as casual sexual partners - I had split up from a previous relationship just 4 days previously, and she leapt at the chance to get into bed! She had split from a long term relationship a month previously and I now realise needed a new victim. She was sleeping with someone else, and had cheated on her ex with him before breaking up (of course) but had fallen out with him so new supply was essential. I wasn't really ready but I was low, and couldn't say no. The second time I told her I wasn't ready for this yet, but she persevered and it happened again. This went on a few weeks until she said she wasn't looking for anything serious so I went out with a platonic female friend for the evening. She saw a photo of us out and I later discovered, responded by sleeping with someone else. The next day she asked me on a date. Turned out it was seeing this photo that made her think of that - she admitted she never actually considered us as a potential couple until she saw me with another woman. So in fact she didn't want me at all, she was just fearing losing her attachment and did what she needed to do.
We dated a few weeks but she refused to commit, refusing to label it as a relationship. After a while she said, "we aren't sleeping with anyone else though, but let's not put pressure on it." Eventually we were a couple, although there was never a decision about that, she just began talking in such terms. But her friends were not to be told, because she didn't want to hurt her ex - it was too soon. I was introduced as "a friend". All my friends had to know though. It was as if she just slowly escalated as necessary to keep me around. She limited our time together, saying she didn't want to scare me off. But now I see, she simply only wanted to see me when she needed it.
A few weeks later she said she was in love with me. Was she? Who knows? Maybe in her own way, but I think she was just reliant on me by then, emotionally. Then the nightmare began. Any women I was friends with had to be cut off, especially the one whose picture had made her ask me on a date in the first place. I gradually did stop talking to my female friends, but the jealousy simply moved into more bizarre areas - I loved the cat too much, expressed concern for a friend of a friend when told she had been assaulted. When I became sad at the sight of a sick child on the news, she burst into tears - I even cared more about someone on TV than her, she said. I didn't put her first. I didn't make her feel special. " I want a boyfriend who cares only about me." But i hadnt changed from when she said shed fallen in love. Now she had me, and was terrified of losing me before she was ready to. I made her insecure and anxious I was told repeatedly. For someone in love, she showed zero concern for my distress at her sudden rages. There was no real love - she needed me for the time being, and I loved an illusion.
I finished it many times, only to be told such amazing things - I was the most incredible guy in the world, she couldn't be without me. She had come therapy, but never really discussed it, went on meds for the rage and I thought she was making an effort and would learn to trust me and it would all work out. But the meds were to make her feel better, not me, and she made me feel guilty for making her reliant on them to put up with me.
When we split she said, it could never have worked out - she couldn't trust someone who moved on so quickly, and even though I no longer spoke to the girl who triggered her interest in the first place, the fact that I had been out with her on that day before we were even together meant we had to break up. She wanted a guy who once they noticed her, never noticed anyone else. "I could never have got over the things that happened before we were together." Turned out, I didn't stand a chance.
She made great efforts to remain friends, for a few weeks, until I realised we were friends only on her terms and stopped it. The final time we spoke she said she couldn't bear to lose me, I was the most amazing man she ever met and she still loved me and always would - she couldn't imagine being with anyone else for at least a year or two. She was in a new relationship within days of saying that, after I turned off the contact.
So I was nothing special to her - she didn't want me, she just needed an attachment for now, and did/said what it took to keep it, until she was ready to discard and substitute. I wasn't lovable after all. Maybe I clung on so long because I didn't want to know this. But now I know it, and feel such emptiness at realizing my salvation was totally false. I'm not sure where to go from that