While Old Age Security is an individual government benefit, you and your ex-spouse may be able to share Canada Pension Plan (CPP) benefits when you retire.
If one or both of you are currently contributing to CPP each spouse has the right to apply for division of the CPP credits earned during the relationship (this applies to marriages, common-law and same-sex relationships). Essentially credit splitting evens out the credits earned by the spouse while they were together.
If the relationship was a marriage under federal law, there is no time limit to apply for the splitting of credits. There are time limitations in regards to common-law and same-sex couples (four years after the date of the separation).
If your relationship breakdown results in divorce you do not have to apply for credit splitting. You simply need to provide information to the government such as proof of divorce and the length of time that you lived together. In cases of common-law or same-sex marriages a formal application will be required.