It will only get worse if this continues and then you will have reached the point of no return. Your husband needs immediate treatment. It is possible he can turn violent if he is not taking medication to control his delusions.
Your concern is your children right now and their safety. Think of them because if it gets any worse they won't have a father. Already you mentioned your husband's self-care and attention to household duties has slipped. This is a clear indication that he is in great trouble as a provider for his family. Especially with the confession you made that he frequently changes jobs.
You could wait to see if he suddenly turns around and is amenable to seeking treatment. However you know that at this point in time he is not. You have only today and you have been given clear signs by your husband that he cannot function well enough to be responsible to take care of his family duties right now.
He is jeopardizing your work situation too by calling you at every hour and harrassing you on the phone when you need to be at work.
You might not want to take a time out from your involvement however you have to protect your kids and establish your own sanity and maintain boundaries even though he is your husband.
It will not get better unless he gets treatment right away. You can set the terms here. Tell him you'll go with him to talk to someone. The presence of a mental illness in your husband is no excuse for him to continue with his behavior.
You need to protect yourself and your kids first of all.
For more support and suggestions you could contact the National Alliance on Mental Illness (NAMI) national hotline to get the name and number of the local chapter in your city or town that has family support meetings.
(800) 950-NAMI (6264) is the number.
Should your husband not be willing to go with you to seek treatment you have other choices.
I will stand by you whatever choice you decide to make.