How to let go of some leftover issues from past relationship?

Hiya kiddo's.

So... you know the feeling, when you're with someone early on, already going out together and you both talk about relationships in general. And when you find out, that you both have the same view on majority of the stuff, you bond very well and feel much more connected to the person.

And the problem is I found out, that most of what I still seem to feel about relationship is memory of being hurt.
A sense of failure, which I feel dragged down by.
Feeling threatened by my making wrong choices & kind of bitterness.
Feeling of being acted unfairly towards to in past and obv. there's still some need to shout it out to the world.

Now all of this is buried kinda deep. Otherwise I'm making everyday little steps towards being a strong individual and like the process. What does one do to let definitely go of the past and start being an open, positive, self-confident, comfortable person relationship-wise?

Bottom line, there is this really fit girl, whom I could start going out on dates with and it'd be stupid to do that with some unresolved issues. Also, have you got some stories of your own about this kind of stuff?

Cheers & thanks
the Black Flux