Then you should just decide how you want to tell him, that's all. You can make it something special, or just choose a time that feels right.

[ He giggles softly, and doesn't explain, letting himself relish a memory without comment. It had been rather fun, how he'd told Zexion, and reading the poem for Genesis had been pretty nice too. ]

Whatever it is, it has to be whatever feels best to you. And I'm sure it'll be all right. Even if he doesn't love you in quite the same way, or doesn't want to change something immediately... he wouldn't be where he is with you if he didn't care about you a lot.