I S.,
Let me preface this advice with a statement. I never think the husband is right.
So with that said, when you are both not being awakened from a peaceful night sleep, try and ask your husband what he objects to most about the boy being in the bed? Does he get kick by the boy (my girl is a kicker)when he sleeps in the bed with you guys? Is your husband affraid of hurting your boy by rolling on him in his sleep. Or is it just purely selfish reasons that he doesn't want HIS son in the bed?
Oh, and are his legs not right? if he doesn't like his son in the bed - let him get the boy back into his own bed. Why do you have to do it?
Both of children co-slept in our bed. My son's bed is still right next to mine and he is 2 1/4 years old.
Just always remember - Your husband is an adult - if he doesn't like a particular thing. It is HIS responsibility to fix the problem, and that does not mean make you do it. It is not your responsibility to make everything in his life perfect. It is his. You do enough don't take on any more responsibilties. Especially not other adults.
Good luck.
B.