My dad has kidney issues. He had a transplant a couple years ago, but unfortunately was misdiagnosed BEFORE his transplant, and now the disease is back and attacking his new kidney. I don't know how bad your dh's potassium is. Dad is at the point, he can basically have 0 (not possible but he has to get it as close to 0 as possible).
It's a HUGE struggle when dealing with potassium. Especially when trying to cook what we've learned is healthy also. What my mom does with the white and whole grains is buy 2 kinds of bread. They usually buy small loaves if they can find it, white of some sort for him, whole grain for her. When dad could have a little potassium, and craved potatoes (or it was T-giving, etc), mom would peel and soak her potatoes all day. This helped draw the potassium out. Not all of course, but definitely some. Beans are something they've just eliminated from their diet. Healthy or not. They do a lot of lean cuts of meat, any veggies that he can have, etc.
I know between what your husband CANT have and what you've learned you SHOULDNT have, it leaves very little. But it is possible. Look online for new and different recipes. If you are making enchiladas (I found one with a green sauce instead of tomato based, and you'd just have to go easy on the cheese (which we would do anyway)) you can roll his up with flour tortilla and yours with wheat. Little things like that.
I'll be happy to help you in any way I can. <hugs> to you both!