You should declare your husband in your application even if he is not going to accompany you to Canada.
As you have already said, it will be considered misrepresentation if you do not.
For your reason, I suggest you tell the truth i.e. the actual reason for your husband not accompanying you. It can be many things - perhaps he can't leave his job currently, perhaps you have property you need to sell, etc. But whatever the reason is, you need to be upfront and honest.
Also remember that you will have to show Proof of Funds for both you and your husband (i.e. proof of funds for 2 people), and your husband will also have to do the medical exam and get his PCCs.
What is the reasoning behind your husband not accompanying you, if you don't mind my asking?