I've been to china and from what i've experienced, they're usually colder than the people from where i come from.
that's not an insult to chinese people mind you. it's just that there are greater things to focus on, i think.
if he forgot your birthday, it doesn't mean he doesn't love you. But from where I come from, us guys forgetting our girlfriends b-days are a big no no and something like that usually gets us killed. well, not killed, but in DEEEEEEEP trouble.
If he doesn't make it up to you though, then this dude has some problems and perhaps you need to have a sit down (means talking with him) with him.