It does make sense for women to have children inside a mariage because it does give them some «insurance» that the men will pay if they get separated. In Canada the divorce and separation rate for first unions is around 50 %. For second and third unions, the separation rate is about 80 %. So, with a mariage they do get at least 50 % odds that the men will pay «dearly».
In Québec, which is particular in that respect, there are three different types of mariages which can be contracted plus the «shacked up» arrangements. The obligations following the breakdown of these different types of unions, differ, from total separation of assets, to the assets gained during the mariage, to no obligations in the «shacked up» scenario. The legislator in Québec purposely exempted obligations for «shacked up» couples.
In Québec, the obligations regarding the children after a breakup are always present independant of the type of union. That is fair. At least, we do have the choice of not getting ripped off by the women by choosing and appropriate mariage.
Good luck to those with the more stringent obligations of some jurisdictions. I suggest strongly that you get at least a prenup, and/or get shacked up.