I met Kip and Prof through online dating, my ExH in a bar in Guam, and my previous long term boyfriend, wow, I don't remember...we were at University. One boyfriend at work, one through friends, another in a bar in Tokyo.
My preference would be bumping into someone on a regular basis and getting to know them that way.
Me: 40s female
Kip: 50s male, married.
Prof: 50s male.