Have I made the right decision breaking up with my partner?

[Josh Emily]

Hi, first time posting a question, have always found these to be helpful

I broke up with my gf 3 weeks ago, and I'm wondering if I have made the right decision.

A brief background.

I'm 23 and she is 18 we met 2 years ago when she was 16 and I had just graduated from university.

From day one she was very paranoid, always checking my Internet history, Facebook, texts, twitter etc. at times I would wake in the night and feel her pulling on my phone from under my pillow to try and get on it. I have understood this is largely down to her age and insecurities.
If I was to add a female or a female to add me on any social networking sites I would get a lot of stick and she would then inbox the female asking if we have spoken at all.
She never liked any of my main friends for no reason what so ever.
She stopped seeing her friends and lost the close bond she had with them so she could spend all her time with me, I was never aloud to make plans to go on trips or holidays with my friends without getting a lot of stick. She was completely against drugs knowing full well I would do them from time to time when at party's or out at a festival etc, so I would get stick for that too. If I was caught looking at another female I would get stick, most of the time I felt I had to walk with my head down.

I'm sure there is more I can tell you but I guess you can get the picture...

Anyway since we broke up she didn't cut contact with me and I wasn't willing to change my number so I have had to deal with text after text and sometimes I would reply just to show I'm still here and care for her. I know I was we everything and first love of her life and it hurts me a lot to see how much pain I'm causing her and keep asking myself have I made the right decision? I do feel happier but then at times I sit and wonder what if I has stayed with her. Would she ever change? Which she claims she already has? She says she will do anything to have me back, should I leave her to enjoy her life?
We didn't move in together we never did, 16years of age is not a child she was nearing 17 when we became a couple I was 21 there definitely isn't a problem concerning our age.