So, I am dating an Chinese man...?

So, I am dating an Chinese man. He's only been in the States for about 3 years and he's just as polite and kind as ever. But, the thing is he is not a fan of PDA, such as: holding hands and kissing in public. He says kissing should be between us and no one else. I suppose this is okay...I am just not use to guys like this. Now, my question is, is this a cultural thing or a "him" thing?