Can a step-parent unilaterally withdraw from that status?

It is useful to begin first with Chartier v. Chartier, 1999 CanLII 707 (SCC), [1999] 1 S.C.R. 242. There, the court considered whether once a person is found to stand in the place of a parent, he or she can unilaterally withdraw from or shed that status. There were conflicting lines of authority on the point in the courts of appeal across the country. Bastarache J., for the unanimous court, answered the question in the negative. He said (at paragraph 39): ...Once it is shown that the child is to be considered, in fact, a child of the marriage, the obligations of the step-parent towards him or her are the same as those relative to a child born of the marriage with regard to the application of the Divorce Act...