I wet the bed well into my kindergarten (and maybe 1st grade??) year. My nephew also had a problem with it. I don't know what my brother's family eventually did for my nephew. But I remember my ordeal well. I had to come home early from my first "slumber party" because I was afraid I would have an accident and end up humiliated. For me, I was a very hard sleeper. I remember having dreams that I was in the bathroom when I wasn't, thus wetting the bed. The thing that finally helped me was a sensor that went between the sheet and mattress or mattress pad that would alarm when it got wet and wake me up. I don't know if they still have those,and i don't remember what we tried before that.
I do remember being really upset about the problem and wanting desperately to not have it any more. I'm sure there are lots of things that could contribute to bed wetting problems, so definitely talk to your pediatrician. But I agree that punishment likely won't help. For me, I was already so embarrassed and upset about it. I can't even imagine how much worse it would be to get in trouble, and I'm sure your son probably is further upset if he knows it is a matter of argument or disagreement among his parents.
I don't know what the problem is for your son and I don't know what the best solution for him will be. But feel free to show your husband my response if you like. We all do our best to try to provide the most constructive and effective parenting we can. And in some situations punishment is absolutely warrented. But I personally don't think this is one of them. I am 37 years old and I remember very well how difficult my bed wetting was for me as a young child. My advice is to support him and help him feel good about himself, that this will pass and you are going to work as a family to make it as easy for him as possible. It may take a while and several attempted solutions. But he will get through it, just like all the other milestones in growing up.
I don't know whether diapers are necessary or not, depending on how often it happens. But I'm sure changing and washing bedsheets is a giant pain and time consuming. Talk to his doctor and try to act like this is no big deal, so he doesn't get any more upset about it. Best of Luck!