When parents separate, whether or not they are married, in a civil union, or have no formal ties at all, both of them must financially support their children.
No matter whether the parents are married and so are in divorce proceedings (under our federal Divorce Act), or are merely separating (under our Civil Code of Quebec), or are dissolving their civil union (also under our Civil Code of Quebec), or finally, are not in any formal union, and so are just taking plain old custody and child support proceedings (yet again under our Civil Code of Quebec), the rules are the same!