The Divorce Act says you can get a divorce act on one of three grounds:
- intentional separation for more than one year
- adultery
- physical or mental cruelty
Most divorces are granted because a couple has been separated for more than a year. See Separation and Divorce for more about this.
It's possible to be separated even though you're still living together in the same home, but you need to prove that you're not living as a married couple if this happens. See Proving you're separated if you and your spouse still live together for more about this.
You don't need to wait a year if you want to get a divorce because of either adultery (your spouse cheated on you) or physical or mental cruelty. But if you're applying on these grounds, you need to be able to prove the adultery or cruelty. So, unless your spouse is likely to admit to being adulterous or cruel, getting a divorce on those grounds will take more time and money than waiting for a year and getting a divorce that way.