You only need to live “separate and apart” to be legally separated.  

In Ontario, to legally separate from your partner, you don’t need to file paperwork in court right away. Legal separation occurs when at least one partner decides they no longer wish to continue the relationship, and both parties begin living separately. While you can live apart, the law also allows couples to be separated while living in the same home as long as they are not behaving as a couple (e.g., sharing meals or attending events together) (Steps to Justice) (Feldstein Family Law Group, P.C.).