I see no conflict with doing the best one can with difficult circumstances and teaching correct principles.
If anything her children will grow up with loving wisdom about these things. Sometimes imperfect examples are the best way to teach broader concepts. Isn't earth life itself an example of this?
Kids have ways of challenging us is ways we don't expect... And in this case she might think the issue is over once she finds a new man that will accept her conditions. I just wanted to give her a heads up that it most likely will not go away by just finding a man.