Why does my boyfriend always have to be touching me when he sleeps and grasps me real tight if he thinks im getting up?

I love to touch my girlfriend when she's sleeping next to me, and "next to me" means as close as we can get. Sometimes we'll get too hot (temperature-wise that is) and I'll back away a bit, but just a bit and not for long. Why? It's just part of being intimate. As far as grabbing you when you get up, it's probably part of the same thing although I'm not sure of this. I can't say that I do this but, again, it's probably just his way of being affectionate.