<human>: Could you distill the essence of the text into 1-3 sentences?

Alright, as you can see from the title we are relatively young but I honestly am not considering this just "high school drama" I honestly care about him. We have been dating 9 months now, and most of the time we are ridiculously happy, but something that has caused strain has been that we are high school students. We are both very practical and mature (or at least I like to think so) so we are aware that our relationship "working out" i.e. continuing into the college years, I believed that we were both on a similar page, which for me was "I'll deal with it when I have to, or if we even make it there." But he fixates on this problem which has lead to other issues, (telling me he loves me them taking it back because he doesn't want to get too attached) I've tried to assure him that worrying about it doesn't impact the outcome. But I feel like I could handle this better with some advice...
I also feel like this has lead to a fluctuating relationship, "come closer, but not too close" "I care about you but I can't care too much..."
<bot>: Boyfriend is concerned about the end of high school and its effect on our relationship, I want to help ease the panic not sure how.