I urge you and your husband to seek counseling. No matter how much we try to keep divisions with our spouse away from our kids, they can feel it. And they are affected by it. Also, kids will play the two of you off each other.
The book “Fighting For Your Marriage” is a discussion on using PREP (Prevention and Relationship Enhancement Program) method of communication. The techniques are as valid with discussing a grocery list as they are with discussing medications for the kids. It is about really listening and really being heard.
I also urge you to look at TBRI (Trust-Based Relational Intervention), developed by Karyn Purvis and run out of TCU. Her focus is on “children from hard places.” It fits in surprisingly well for kids with disabilities. There are many videos on YouTube that discuss various techniques. NOTE: In the videos, they discuss children who have been neglected and abused. Learning and apply the techniques is not a comment on your parenting skills or love for you children. It is a technique that works equally as well in a well-adjusted, healthy family.