I am the "other woman"

I am the other woman. This is not a fun spot to be in, not what I have ever envisoned. It started out all so innocently a few years ago. I wasn't looking for a relationship, didn't want one. But what I do know, this needs to end. I just don't know how to go about ending it for good. Oh we have tried so many times to end our affair. Each time, weeks, months go by, but we end up together. What really makes this affair so ridiculous, it is all online, we have spoken on the phone, sent gifts to each other. We even have made plans to be together, maybe it is a good thing that we are separated by 750 miles.
My hopes are that I can put my thoughts down here, no one knows me, no one can judge me, but writing this all down, maybe I can finally end it. I never wanted to be the other woman. I wouldn't want it done to me.