Ex Girlfriend Confusing Me?

Quite a long story with my ex....

We got together in january, I met her on her first night out in town after she'd turned 18, I was 23 and the first person she'd been out with. We dated until the middle of April when she became more and more distant then suddenly dumped me saying she didn't feel like she could be herself around me and didn't feel like she could be in a relationship anymore. I took things badly and had a go at her for not saying when something was wrong etc, then wwe stopped talking for a bit. A few weeks later we started talking again and agreed not to see anyone until after her exams and that we were going to give it another go then, then suddenly she stopped texting me after two weeks and then said "I've met someone else and have moved on, I hope that you can do the same", so I said fair enough and got on with things and didnt contact her again, but kept in touch with one of her mates, who said the person she met she didn't even go on one date with, it was just someone she quite fancied.
Then in the first week of august, she messaged me on facebook saying she was really sorry for the way she acted and basically wanted to meet up, so we met up again a couple of times, and everything went really well. She asked if I wanted to go on holiday with her, and since things were going well I agreed, so we booked up a week away together. As soon as I booked it she became quite distant and started acting strange again, then for the majority of the holiday she acted really distant and didn't like me trying to kiss her etc. I assumed she just wanted to be friends because of this but one night we had sex, which was a big deal, because we'd only had sex once before which was when I took her virginity. We discussed getting back together a few times, and she said she didnt know what she wanted and when she knew she'd let me know, even if it was just to be friends. When we got back things were going well again, then after a week she suddenly stopped replying to my messages, so I lost my patience and said forget it basically, then she said she didn't feel the same anymore, and I asked why she didnt tell me like she said she would, and she said she wasnt 100% sure until I text her saying to forget it and it turned out she'd been telling me one thing about getting back together and her mates the complete opposite. Anyway I said being friends wouldn't work so we left it on good terms. I texted her today asking her about something and basically got the cold shoulder again for no apparent reason, 3 weeks after going on holiday together! Any ideas why she's acting like this?

If her behavior seems strange, it's because there is somebody else in the picture that you don't know about.

The only other person is the guy she said she fancied when we split up, but she'd already known him ages anyway because he was engaged to one of her mates. She even said they bumped into each other on a night out after our holiday, said she still fancied him but didn't wanna get involved because where he'd just split up with her friend and was going to uni in like 2 weeks. They'd never even been or a date or anything though I'm certain. Just can't understand the whole insanely hot and cold attitude and saying she wants to be friends then getting in a mard if I casually say hi?

Wow, she's a right spoilt brat.

Sorry, but if a guy was acting like that to me, I'd be calling him out about it when I notice it, not when they decide something is wrong, etc. Ok, so maybe it's the same reason I'm single, but at least I haven't had to take crap from them.

She doesn't seem mature enough to be in a proper relationship with anyone, from her behaviour. She can't even be honest and open about her feelings to you, and practically ignores you when she feels like it, but then she comes back to you later on. And what's just as worse is that you take her back!!! Why?!?!? Do you really think she'd change??? She's still young after all, relationship-wise it sounds like she has a lot to learn.

Well to be honest I'd be giving her a bit of slack because when we got together her mum found out she has huntingtons diease, and it's worrying her a hell of a lot, she kept talking about it on holiday, and when we got back said she hadn't text me for a bit because she'd been in and out of hospital and they thought it might be linked to her having it......That and she's ridiculously hot and I have very little will power lol.
I genuinely don't want to be in a relationship with her now, I'm not gonna lie I'd sleep with her in an instant because I still find her extremely attractive, but really have finally lost my rag with her. I just can't understand how phenominally hot and cold she is, even her best mate sided with me on it, and her best guy mate doesnt even want anything to do with her because of how she's lied so much to me and her mates about the two of us. Like even today I was trying to be all jokey and friendly and she was all "yeah I'd appreciate it if you dont text me, you said you dont want to be friends" so I said fine I'd delete her number and remove her on facebook, went to do that and she already had lol. I just cannot see her side of things as to how she's being anything other then a spolit cow?

She is not very mature. Most of that is probably because she is just 18 years old. It is all your choice though. Too immature for you? Look for someone different.