Both OP and SoThatHappened
It's not them, it's you. But not in the way that you think.
SoThatHappened: they never make you the girlfriend because you are choosing emotionally unavailable men that never make anybody the girlfriend, despite what you think you have seen on facebook / heard.
It's you because you keep on choosing people like this. Because as well as being dysfunctional duchebags they are often good looking, charming etc. But they fire your radar for other reasons. And the cycle they set up is addictive (for you) and interesting / exciting (for them).
What you are feeling isn't love, it's addiction. Like caffine or nicotine or alcohol (to excess) you feel awful without them, and brilliant with them. But not because they are being brilliant for you, but because the relief and brief respite from being without them or alone feels great.
I spent my 20s in a serious of 'relationships' like this. The sex was invariably great but otherwise it was crappy, and it took its toll on me until I couldn't do it any more.
Read this en.wikipedia.org/wiki/Limerence and this www.baggagereclaim.co.uk/about/ and then get yourself some therapy. Figure out why you choose these duche bags, and then do the pick me dance (personally, it was because my father was the original Mr Unavailable. It's the most usual explanation. But not always. But it's usually something like that. Childhood, family dynamic etc. are highly likely to be part of the reason)
I did NLP, both one on one and then the practitioner course. I loved it as it helped me not just see the origins and pattern, but gave me a framework for changing not just my choices and behaviour but also how I felt.
I took some time off all romantic relationships. Then went back with a new approach and some clear bottom lines from me.
First one was a douche, but this time, I'd not slept with him before he fessed up that he was 'actually seeing someone who lived outside the UK' and although it was on its way out, things were a bit complicated so could we 'be friends' for now?
I said, sure, if your definition of friendship meets mine, which is regular communication, returning messages, no trying it on. And 'no thanks' if he meant 'Can I call you when I feel like it, ignore your messages when i dont, try it on when I want, sleep with you if you're willing, all with the 'but we're just friends' get out card already on the table which meant I couldn't complain about it'.
He laughed, said that was a bit intense, but he took the point, said he'd call me Monday. Unsurprisingly I never heard from him again.
And number 2? He squeezed in our first date before he went on holiday. After that (no sex) date, he'd arranged our second before he got on the plane to go. On the third, he forgot his wallet. He made an excuse and ran back to the office to get it rather than let me pay for dinner. He alwasy called before i had the chance to wonder if he would. He's my husband, we have 1 DC and another on the way. I'm very happy.
If I'd met him at any point in my twenties I wouldn't have given him the time of day, or even noticed him, as I would have been looking over his shoulder to his charismatic f*ck up of a friend / colleague / guy on the next table. And I have to take responsibility for a decade of bad choices.
You will be the girlfriend. To a man that you choose to be your boyfriend. But to get there you MUST sort out your issues rather than reliving your destructive traits and hoping the person least likely will save you. he won't. Believe me, he's too busy avoiding his own problems.