I think the quickest way to fix this is to apply logical consequences to your HUSBAND. Tell him, "okay, if you think nothing should be done. Then you can handle all the discipline - if you think I'm not doing it right".
Then step back for a few days, even a week or more and let him handle all the problems. He will realize that there will be a need for discipline. And when the kids go crazy, make the home unlivable, and there's no order but only chaos...JUST LET IT HAPPEN. Then he will come to you and BEG you to join him in disciplining them.
That's when you can finally sit down with him and have GROUND RULES on how you BOTH must always see eye-to-eye and be on the same page. And ABSOLUTELY NO undermining your authority IN FRONT OF THE KIDS.
It will be hard for you to let go and let things happen with him and the kids, but if you try to jump in too early ..it will not work. And right now, sitting down with your husband is useless..otherwise you wouldn't be writing us this question. 'Cause I'm sure you've had many conversations with him over this already!
Let him experience what it's like to have children who do not respect discipline or rules. You're life will be chaotic for awhile, but stay on the sideline and just let it happen.
Sometimes people have to experience it for themselves before they get it.