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

[MB]

Unfortunately, people like that rarely change. (There is a chance, just not much of a one)
They may act like they do, suppressing the need to act, but deep down, will most likely be as insecure and be wanting to give you as much stick.

My suggestion would be to try hanging out as friends, and take things slowly from there, as if dating for the first time again. You seem to still love her, but just hate all these negative things she is doing to you. I believe people deserve a second chance.
If she ever has urges to peek at your online stuff, peek at your phone, etc, then tell her she needs to try and trust you, otherwise it can't work.
Every now and then, show her your internet history yourself (if you ok with that), or something like that. This will show that you are honest and open with her, hopefully getting her to trust you little by little.

If this still doesn't work, then it might be best to break up permanently.
Relationships need trust. Explain to her that you need it.