Ok - imho..... you have to pick what you want to do. I would start big. Do you want your son to sleep in his own bed. Is that important to you? Why? (you don't have to answer to me..... just to you and hubs and son).
If your goal is to get him to sleep in his own bed..... THEN you can see what works for him. You've said 'several months' and then 'several months' so I'm guessing....... 7 months?
Most experts say that CIO will really only work if they are older than 9 months. Before that babies can't connect a consequence. They just *are*. So you may get a baby to sleep in his crib by not going to get him when he cries, but they aren't really going to be able to connect anything in their mind that *now* it's time to sleep and they sleep in their own bed. However, between 9-12 months is the *right* time according the experts.
People who use CIO *correctly* have a high success rate. But you can't cave. You absolutely cannot cave or not only is it ineffective, but it will backfire. cuz now your baby knows you're a sucker. So it will take even longer for this to be effective.
the bottom line is that you and hubs have to decide what's right. If you co-sleep, then co-sleep. He'll go to his bed when HE's ready. That's the POINT of co-sleeping..... to let the child go when they're comfortable. But if you co-sleep then be consistent with that. No kicking him out when you want to do the hanky panky or when you're crabby.
An 18 month old doesn't understand why all of sudden the rules are different and now I have to sleep alone for no reason tonight. Just like they don't understand why last night when I cried mommy came and cuddled and tonight she's leaving me alone. You have to be consistent, which is the hardest part.
I can tell you that we co-slept, sorta. not because we wanted to.... but because that's what worked for us. She started out in her crib. Lots of times she stayed there the whole night. But sometimes she cried and I went and got her and brought her in bed with us. And we ALL slept much better. When she was 3 she slept in her own bed for the better part of a year. Then her dad and I divorced and she slept with me for the better part of being 4. At 5 she was in kindergarten and wanted to be a big girl so she went back to her own bed... .mostly. Every so often she would come get in bed with me. Last week..... the night after her first day of Jr High she would have slept with me if she could have, but I'm engaged so we have different rules now :-(
That doesn't work for every child or every family. So, figure out what your overall goal is, how you want to accomplish it and then you and hubs be consistent.
Good Luck.