Dear Sis:Tonight is my first date with a person I’ve met online. It included drinks, food, and a good dose of flirting but nothing more. He seemed charming, but I decided to play it slow. The bill arrives and we both reached for it. He said “My Treat” and picked it up. I offered to chip in, but he refused. I felt uncomfortable, but I let it slide. As we said our goodbyes, he invited me…