Um..."I’ve been seeing a guy for just over 2 months. He’s made it clear that he’s not seeing anyone else (and hasn’t the whole time). Same goes for me. Other people refer to me as his girlfriend and he doesn’t correct them."

Well from the first 3 sentences, I figured you were together? I just figured when you're seeing someone, that you're dating...especially over 2 months. Just talk about your short term future together, and maybe a long term one. Just talk to him about life in general and where each of you want to take your lives. I wouldn't be so direct with it, unless you want to. Beat around the bush a bit, a bug's bound to fall out.