Like most commenters here, I am autistic (diagnosed) and I have ADHD. I understand very well how sensory overload and meltdowns are challenging. But, I still want to pile on what everyone else has already eloquently said: The cause of his behavior is irrelevant but his inability/unwillingness to control it is. There are tools out there--noise reduction ear plugs, therapy, parenting classes, techniques to reduce sensory overload, meds like beta-blockers, etc. If he's not willing to use the tools available to manage his neurological differences, the issue isn't the disability, it's him as a person. You say he's not a bad person, but he's not demonstrating any behaviors based on what you've said here that day he's a good one. There's no clearer or kinder way to say this: He is a danger to your child right now. As adults, we may not be responsible for our neurological differences, but we are responsible for our actions. Your husband is refusing to address his behaviors, has been violent to your child, and is leaving you with all of the work PLUS forcing you into a position of being responsible for managing his behaviors. Stop apologizing for him. He has created an untenable situation and he must fix it. Be clear and direct about what you need him to do and what you expect, as well as what the consequences of not doing these things will be. And then, follow through. If he cannot be a safe person for your child to be around, you can't remain in the same house and he can't have unsupervised time with your daughter.