It's Metafilter's 20th anniversary! To celebrate, scan some cats or help fund Mefi! How do you gently tell someone you're casually dating that you're also dating someone else? This has come up several times in my dating life, and I've been consistently stumped as to how to respond. I - a girl - will meet a guy. I'll start casually dating said guy by "casually", I mean: we're not sleeping together, we don't have standing dates, we're probably not meeting each other's friends, etc.
A friend once told me his test of whether he's over an ex is whether it would bother him if they were dating someone else. Under that logic, I've never gotten over anyone in my life. Months and sometimes years after a relationship, my heart rate still accelerates when I see an ex is dating someone new on Facebook. Over a year after I ended one relationship, I found some photos on Facebook of my ex with a woman I didn't recognize. It was like we were still together and he cheated.