I've noticed that as well, and had a way around it. My wife and I were playing at the same time, and basically we did a count-down before we clicked Find Game button, and we were paired against each other. I'm not sure how well that will work with the latency in the game, and using the room's chat.
I read somewhere that they base the matchmaking off how many times you disconnect, which makes sense to have those that disconnect play others like them, but besides that I do not think there is much rhyme or reason behind it.