Hey Moxie! 
I can totally understand your situation.  I agree with Hootie when she said maybe you two are acting more like a married couple rather than a youthful couple.?
Maybe he has other stuff (school.. maybe work?) that is 'distracting' him and he doesn't really see the whole plateau thing.
I think if you both want the same things out of a relationship, it can work out.  But if he just wants everything to stay the same and you want things to grow (I'm not talking marriage tomorrow or anything! 

), then maybe both of you should re-evaluate things and if they dont match up, maybe right now a relationship between you two is not the best thing?  But that is something the both of you should decide.  I agree with Hootie - follow your heart

 I really hope it works out for you Moxie!