dude id forgive her, and at the same time keep an close eye on her.
She at least told u about that witch means she feels somting for u, so dont dred on somthin that happend a year ago, work on what u have now, but lett her know that ur serious about her.
Comunication in a relationship is one of the keys to happyness

Peace bro and hope itall works out for the two of ya