What is love?

Is it loneliness? Is it the desire for something new? I am not sure, but what I do know is that I must stop playing with this any further. Having this man back in my life feels wonderful, but it simply isn't appropriate.
We are so familiar with each other. The conversation moves so nicely, the memories, the jokes, the questions and answers about our present and future, all make this even worse.
I do not even think that this is a moral issue, but a practical one. Women go through this sort of thing all the time, your told his sob story and before you know it, you are the 'other woman.' How did it happen? You didn't see it coming quite so fast did you?God, to be a cliche! Ugh!
I don't want that role. I love this person, and I told him that I care about him enough to want to make sure that we'll be better off if we just remain friendly.
But I didn't do that, did I? I took it, and he took it to another place. Sure it wasn't very far, but it was far enough, because I found it all confusing. On the one hand, my desire to keep it neutral and then my curiosity to see what would happen next? This contradictory nature cannot survive in one place, or one person. Why am I doing this?
The old memories of us were so close to the surface, and his feelings were like old times. But we are older and everything is different now. What am I doing? I obviously cannot let this go on, and I know I have to just cut it off completely. We'll just have to live on memories until things change (if they ever change) for him.