Jason Mercado and Kristen Bateman, who met 10 years ago, didn’t begin dating until after three months of emailing. “I wanted to become friends first,” Ms. Bateman, a self-described introvert, said.

Jason Mercado and Kristen Bateman, who met 10 years ago, didn’t begin dating until after three months of emailing. “I wanted to become friends first,” Ms. Bateman, a self-described introvert, said.