Where to look for co-op partner ? (esp. in Original Sin)

I'm looking for someone to start a co-op campaign in Divinity Original Sin which is the only one game I like to play co-op and none of my friends has it. I tried the discussion thread on Steam but most people go there to report bugs or talk about the game. Anyone has a suggestion for a place that I can find people to play co-op with in general, DOI in particular?