Why is he hiding me?

I don't think that's the case. Maybe your more open to having someone around your family unfortunately that's not the case for everyone. He might just be a personal guy who doesn't want the opinions of other's affecting his view of you. On the other hand you did say you two have been seeing each other for awhile. So my hands are tied with this one. He loves you? I'm not sure but time will tell. Just let him in on how you feel if he truly loves you he'll make a few changes if not. His lost

Maybe he's not hiding you at all maybe, like you said you don't get attached easily, he might not really think your a couple or if he does , maybe his family isn't the type that cares about what their kid, brother,cousin or whatever does, maybe he's afraid they won't like you and maybe slowly assimilating you into the family letting them gets you for you first. There's a number of things it could be hope this helps at least you know more about the situation than I (and I would hope so lol sorry not very good with jokes but I try) but hopefully this will narrow it down, maybe you should like confront him about it kind of be like hey how come you don't o this it kind of bothers me. Hope this helps!

Depends on how long you two have been dating. Or maybe he's embarrassed of his family?