Welcome to the forum. I too am sorry to learn how much you are struggling. I hope we can help and support you through this time.
Geoff is quite right when he said you need to look after yourself. This is vital as your family need you to be well and able to be a part of family life. My feeling is that the more you support your husband the less time you have for yourself and family. It also teaches him you can help him out of his depression and so he does not need professional assistance. If he has never had counselling he cannot say if it will or will not help.It may be time to not be available to him when you are not feeling the best or when someone else needs your help. Your children are presumably quite young and need lots of nurture from you. You cannot do that while giving your whole attention to your husband.
I hope I do not sound as though the role you have is support for family members. You do need to join in all the facets of family life. I also wonder if you were not so available if your husband would start considering other avenues of help. Getting him to see your GP would be a great first step.
I know it sounds mean not to help your husband but I also feel it is mean to expect you to cater for his difficulties at the expense of your own. We are all in need to help and support and we are all worthwhile enough to get it. If you are not so readily available and he asks why perhaps you can explain to him that there are others who need you as well as him. It may not have occurred to him.
Please go the The Facts at the top of the page and navigate through the drop down list. You will find a great deal of information there including a booklet written for family and friends of someone with a mental illness. You can download the fact sheets but must send a request for the booklets. There is no charge and I think it will be helpful to you.
You may also benefit from a visit to your GP and a general check up. You do not sound depressed but you do sound very tired and careworn. Your GP may prescribe something to help manage the tiredness. In any event he/she will know what is happening for you and may be able to give you some advice. Perhaps print out your first post and take it to the GP.
Love to hear from you again.