Hi there, welcome to the forums
Years ago when I was a teacher's aide for 2nd graders, I saw this so often, it is very difficult when spouses cannot agree on discipline, boundaries, it can frazzle the most patient parent.
It sounds like a situation where family counseling may benefit your family, and you, of course.
I do not know where you live or what kind of area, rural, suburbs, etc. but in many locations there are family counseling groups or private practice.
It is so important for you and your husband to set guidelines and consequences for your child or children, a counselar can help all of you to see what may work the best for your family, it can be of help for the stress it puts on relationships and/or marriages.
Behavioural problems often stem from inconsistancy of parental guidance, support and boundary setting.
More so than the trend of DXing kids with ADD/ADHD, which has become a "catch all" for behavioural problems, sad too, some parents think that is the problem and get kids on to meds when so often unecessary.
Kids need structure, limitations as well as rewards.
You are more than welcomed to discuss stuff here, so many parents can relate to this topic and may have some good pointers.
Getting a spouse into counselling can be tough, many are in denial that they contribute to a problem, but it is worth trying to convince him or her, in the long wrong it is the child's future and all parents want them to go forth in the world, happy, well adjusted, and hopefully respectful to others.
Well, I have to go harness my 2 dogs in the car and pick up my son, hope I was of some help to you.
Parenting was and still is not an easy thing, but getting some outside help can be a blessing.
When help is sought by family members, parents and in-laws it can get kind of sticky, too many bias to either side, and causes more confusion possibly leading to conflict . . .
not a good environment for kids to be in, especially when behavioural problems are the issue.
Lots of luck, in time the child grows, learns, and things will brighten providing there is a strong foundation . . . you'll make it, mom.

Sincerely,
DE