What can I do when my husband with Lewy Body Dementia is getting violent (throwing things, etc.)?

I don't know the extent of his behavior, but, please make sure you are safe. I would call for help if necessary. Sometimes people do not properly take safety risks very seriously. I hope that you both remain safe.

Have you contacted his doctor? I would seek immediate help and report any change in mental status to his doctor. I'd ask for medical advice as to how to proceed.

I can only imagine that it would be very frustrating to deal with dementia. I might read lots about dementia and Lewy Body dementia. He likely is not able to conform to the behavior that you would like. It's not common for dementia patients to understand, accept and show appreciation. The opposite is more common.

I would seek help to help with his care. Is he at a level that he can still communicate with others? If so, he may consider communicating with other people who have Lewy Body.

When he is violent or throwing things, call 911 for help.

As Pam says call 911. He can't help this kind of behavior and you can't stop it. Be prepared for him to need memory care before he really hurts you. Has he been violent all his life? It is not your fault so doing the right thing is best for both of you and actually the loving thing to do however much it breaks your heart to see him like this.