My ex wife and I co-slept with our kids when they were little and generally the kids themselves start to claim their own space when about 18 months - 2 1/2 years and so the transition is easy. Just take your que from your child, and all will be well. I have to agree with your husband, both my ex and I were very anti the 'controlled crying' idea.
We've since split up and she has had 2 sets of twins in quick succession with her new partner and they are I know co-sleeping with the littlest set and were co-sleeping with the elder set until the birth of the new babies.
I've gotta say that none of my own children or hers that I've seen recently, have been difficult to settle on their own, as co-sleeping gives them a feeling of security and self confidence that I don't think non co-slept kids get.
My eldest daughter we did this with is eleven now and is a very stable, happy, confident girl, far more so than the kids from my first marriage who were not co-slept.
It's anecdotal i know, but if I ever had further kids, I would definately want to co-sleep as it's so muich easier and less hassle than the whole bedtime routine, hours of crying thing so many people seem to have, plus it's natural, how many animals do you see that sleep seperately to their young? I seriously don't think we ever had a sleepless night with ours.