"..A parent's liberty interest in the care, custody and companionship of children cannot be maintained at the expense of their well-being. While visitation is a key element of reunification, the court must focus on the best interests of the children 'and on the elimination of conditions which led to the juvenile court's finding that the child has suffered, or is at risk of suffering, harm specified in Welfare and Institutions Code section 300.' " ( In re Julie M. (1999) 69 Cal.App.4th 41, 50.) Accordingly, a parent who has failed to reunify with his or her child and seeks to avoid termination of parental rights by invoking the exception in section 366.26(c)(1)(A) has the burden of showing that the benefit of continuing the parent-child relationship will outweigh the benefit of a permanent home with new, adoptive parents. ( In re Jamie R. (2001) 90 Cal.App.4th 766, 773; In re Melvin A. (2000) 82 Cal.App.4th 1243, 1253.) A parent may not invoke the exception simply by demonstrating some benefit to the child from a continued relationship, or some detriment from termination of parental rights. ( In re Jasmine D. (2000) 78 Cal.App.4th 1339, 1349.) Instead, the parent must show that he or she occupies a "parental role" in the child's life. ( In re Derek W. (1999) 73 Cal.App.4th 823, 827.)