<human>: Well my fiance came over when I got home from work today and said we needed to talk. Figured it was something about our wedding because we are set to get married 9/2015. She says it is important that we be honest and that she had been unfaithful to me about a year ago. She had sex with a coworker twice. She said she has no contact with him anymore. I am guessing that is because I proposed to her shortly after that time. 

I am absolutely crushed. I am so confused and I feel I don't have anyone to talk to about this. She is my best friend and the love of my life. She begged me to forgive and pleaded that she wanted to spend her life with me. I asked for her ring back and told her I needed to be alone. 

I guess I am just looking for advice. She is a wonderful person and I couldn't imagine my life without her, but right now I am so hurt I don't even know how to deal with this. Should I forgive her? Should I leave her? I feel empty inside. We have been together for 6 years and have known each other for 10. She did seem sincerely sorry and ashamed of what she did, but how could she do this to me?

Can you give me the gist of the text in a nutshell?
<bot>: my fiance cheated on my with a coworker about a year ago. Just looking for advice and people to talk to. Fuck this sucks I could never imagine her being able to do this.