My dog never sleeps in my bed =(?

My 3 year old shih tzu Pandy (he's black and white) has never liked sleeping in my bed. Ever since he was a puppy he would let out little whimpers or grunts of frustration until I put him down or he jumped off himself. I know he must prefer the cold but he sleeps on the floor right next to me. I have a wooden open drawer or "cubby" which he sleeps in. It's wood so I guess it must be cooler but I see him sleeping on carpet all the time and my sheets are cool if anything. Trust me he loves me to death. Follows me everywhere always trying to lick my ear, cries if I leave him. I wish he'd sleep on the bed, I feel bad him being down there. I thought he would like to at least as a puppy but nope. Why is this? The only change I can think of is that while back we started putting him outside more often since my sisters chihuahua started a marking war but he's back inside now and always been like this so I doubt it has anything to do with it. =\