When differences result in divorce.
The office of the Immigration, Refugees and Citizenship Canada (IRCC) department does have a variety of rules and specifications that they outline on their website and through other publications. They list a variety of stipulations that must be met, including prerequisite paperwork and other requirements, that must be considered by anyone who wishes to sponsor another person for entry, regardless of prior marital status.
"If you already sponsor a spouse or partner, you cannot sponsor a new spouse or partner within five years of becoming a permanent resident." This particular rule was implemented on March 2nd, 2012, when the Conservative government brought this measure into motion in an attempt to prevent the abuse of the sponsorship program.
If this is the case, you may wish to petition under these circumstances. Simply follow the process that married couples go through, but be mindful that your sponsorship application will be subject to close inspection due to the atypical circumstances.