How do I tell a colleague that I won’t have an intimate relationship with her without hurting our work relation?
Background
We have been working together for a few years; she was single and I was not. I became single a few months ago and I noticed that she could be interested in dating me. I liked her and we went out once or twice as friends. She invited me to a happy hour with a few of her friends and long story short: she left with another guy in the end (yes, I was mad!). The next day I called her and she obviously regretted, blaming alcohol and apologized...
The problem is that we work together and we always had a very good relationship at work and even though I see that she is hoping to get me back, I believe that I need to tell her that we will never be more than friends now.
My goal
I want her to know that what happened has ruined any possibilities of moving beyond friends (without blaming), but still keep our good relation at work. The other possibility is not to tell her anything, but I am afraid she will try to get me back and it might hurt her more in the long run. I don't see an easy way to talk about his.
Any ideas?