You can sponsor your spouse or common-law partner. For a spouse, you need to be legally married. 

For a common-law partner, you are not legally married but have been living together for at least twelve months in a conjugal relationship. 

For conjugal partner, you are not married and you cannot live together due to circumstances beyond your control.

The sponsor must sign a three-year Sponsorship Agreement that obligates him / her  to provide full financial support to the partner for three years beginning on the date that permanent residence is granted. 

This obligation remains valid even if you divorce or separate from your partner.