Missing my little cosleeper

Din has been sleeping in his big boy bed in his own room nearly every night now.  Well, he starts in there and 2 to 3 hours later is in our bed.  Which is fine with us all right now because after nearly 4 years of cosleeping, well you get use to having a little body cuddle up next to you at night or kick you in side repeatedly.  He wants to be like some of his little friends and be a big boy and do big boy things.  He also wants bunk beds as one of his friends has. So I told him when he is sleeping in his big boy bed from bedtime to 6:00 am, then we'll talk. Every night, the amount of time increases even if it's only a half hour longer than the previous night it's great progress.  Tonight he has been there for nearly 2.5 hours and every other minute I keep thinking I hear him and I'm jumping up looking for him only to find him sound asleep in his little bed.  But truth be told, I want to see him, I miss him and I want him to succeed but it's hard on us mommies and daddies too who are so use to cuddling with him at night.