One question:
Who got the status in Canada first? Did you become a student first or did your husband became a student?
The person who became a student first will be considered "principal foreign national" (
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals/temporary-residents/foreign-workers/exemption-codes/public-policy-competitiveness-economy.html).
The principal will remain principal and can not become dependent and acquire a SOWP.
So, if you got your Study Permit first, you will be principal foreign national and you CAN NOT get SOWP under C42 condition.