Bee and I first met in person for afternoon drinks for a random reason, but I quickly upgraded our outing to dinner and made my interest clear. Then I asked her out for a second date - not quite the same though, because by then we had hit it off.
I am not interested in people all that often but when I am, I definitely prefer to just ask someone out. It's hard for me (introvert) but I find that it kind of simplifies things if one person expresses a clear interest. But when relationships start in friendships, it's not always that easy.
Did your SO ask you out?