hey, this is my scenario too. my fiancee got accepted to university and i am applying as a common law dependent. we have to fill out the statutory declaration of common law union imm5409 and hopefully i will be able to join him in canada and i am planning to apply for a OWP.
"For spouses and common-law partners, Open Work Permits are generally issued with a validity date that coincides with the period of time that their spouse is permitted to work or study in Canada, as the case may be."