I am not answering for seesaw, but what came to my mind is how my daughter keeps her own house. (she is an adult now and owns her own home) . My daughter keeps things simple, so she doesn't have clutter. So perhaps you may want to see how you can arrange your home to minimize the things that contribute to clutter. That can make it easier for you, and easier for him. Yes, it's often something that does upset them, clutter.

My husband is different, he tends TO clutter. So that challenges me because he is contantly cluttering.

This is all good because it will give you things to talk about with the therapist too. It will help when the therapist understands the overall challenge and can help you both work through this challenge while at the same time respecting how you are both being affected.

Try to keep in the back of your mind, what he wants is to be appreciated. It's what YOU want too. So what you both have to work on is finding a way where you both can feel appreciated despite whatever isn't perfect.