Is second chances the correct choice?

From 29/10/10 to 29/10/11 I dated an boy.. And the day we did one year anniversary, I discovered he was flirting with another girl.. We broke up, and I suffered months because of him.. I didn't know what to do, or how to do without him.. After the new years I had changed, my personality, my way of dealing with problems and people.. I wasn't the same person I was before, maybe more cold, but stronger! Some weeks ago, I gave him a second chance, we are taking it slow and seeing what it will turn out.. But, I don't know if i made the right decision.. How can trust him again? After 8 months practically without even talking or looking at each others face, we are 'together'.. He just sent me a message.. I am wrong to feel wrong?