I must say that when we have another baby I would like to do the co-sleeping thing. My baby will only sleep in his cot, in his room, in the dark, alone. I would love it if he would go to sleep snuggled between my husband and I. Sometimes I think of moving him into our bed once he is already asleep so that we can all sleep together!
I wouldn't worry about it. He'll come round soon enough. Our first son was the same. Slept on his own in his room from day one. Has always been a fantastic sleeper. He slept with me during the day as a baby but we grew out of that when he got a bit more mobile. It was then about a year before he ventured back into my bed. Just wouldn't do it. Now I'm pregnant again and we've taken to having a nap together during the day in my bed. It's really lovely. I don't bother closing the curtains because I want him to get used to sleeping in different conditions. We put on a story and fall asleep listening to it together.
My second son is 16 months and won't have a bar of sleeping with me although he also slept with me during the day when he was a baby. I'll just wait til he comes round in a few months.
I know some people like to co-sleep but my husband would never tolerate it and I can't blame him. It's some of the only 'us' time we have together and even then I'm forever talking about the kids!