I would advise against not having your wife as cosigner. If you do, you would have to justify it and saying you alone can pass the minimum threshold is not usually enough.
It is expected that if you are married, you would be cosigning as you live in the same household.
Different case if you separated or if there is any other unique reason.
I alone made more than enough income to sponsor both my parents but I still had my wife as a cosigner.
As for family size, it will be 3 for you. It doesnt matter whether you wife is depending on your income or not.
It is the size of household + number of person you are planning to sponsor + anyone you might have sponsored before.
Thanks Mk,
My wife doesn't have notice of assessments as well as employment history in Canada as she works for minimum wage and also it is continuous work. She goes for work for a week and another week she sits at home
so dont know whether to add her as co-signer. She is new to Canada. She came last year and we both Got PR this year under express entry (I was main applicant and he was dependent)