Ten years!! Move on. Leave well alone. It was, in your own words, VERY casual. As a man if a 'very casual' ex contacted me after ten years I would at the very best think that she is obviously a bit desperate so I might be on for a bit of a no strings attached fling. At the very worst think she may be a bit of a bunny boiler and run away very fast. I notice you have asked what men generally think. I wonder what the women think. Could be interesting.