Don't make the mistake of going back.
keep moving forward and only look back when you need to draw on learning experiances..

I would guess that trust is 90% of all relationships, in your heart of hearts you KNOW you can't 100% trust her.. and that alone will be what makes your next 1-15 years with her (if it manages to drag on that long) and absolout misery...

If your new chikkie makes you happy, draw on that heavily.