Well, the debate is over. He told me last night that he isn't ready to settle down or get married anytime soon. He said he would be fine with waiting to get married until he's in his 40s. He told me the exact same thing only 1 month into our relationship, but I chose not to listen to it. I chose to think that he'd realize how awesome and great I am, and would change his mind... just like in the movies.
So now that something long-term is out of the question, the sex issue is off the table because I don't want to "add to my number" if I know there's no possible future with someone.
Thank you to everyone for all of your advice. I showed a lot of it to my boyfriend last night, so I think it may help him in the future. A lot of you made some really good points that he had never considered.
You guys can keep contributing to this thread if you want, but I'm not sure how often I'll be checking it out since it's no longer relevant. But we'll see... it's interesting to hear everyone's perspectives.
Thanks again!