When it comes to the nuclear family, the level of conflict determines how the kids do in terms of aggressiveness, success at school, self-efficacy, and self-esteem. The following is a section of a report I did on joint custody for a class at Nearby U.:
Bauserman (2002) and Thwaite, et al. (1998) show that children in any joint custody arrangement (either physical or legal) have outcomes that are significantly better than children in sole maternal custody and that there is no significant difference between children in joint custody arrangements and those in intact happy (where happy means that the level of conflict is low) families (Bauserman, 2002, pp. 95-98; Thwaite, et al., 1998, pp. 49-50)....
Thwaite, et al. (1998) show that interparental conflict is harmful (p.24-25) and that parental conflict is “related negatively to children’s post divorce adjustment” (p. 251), but studies of children from both intact and divorced families show “that it might actually be the level of parental conflict that predicts poor psychosocial outcomes among children rather than the divorce itself” (p. 251). In other words, divorce is better for children notwithstanding the common practice of staying together for the sake of the kids. Both the Gunnoe & Braver (2001) and the Bauserman (2002) studies agree that, contrary to the belief that shared custody continues pre-divorce conflict, there is no increase in parental conflict in joint custody situations. Indeed, Bauserman (2002) reports significantly less conflict between parents in joint custody: “in fact, it was the sole-custody parents who reported higher levels of current conflict” (p. 97).
In other words, parents who stay together "for the sake of the kids" are worsening their children's chances of success. Sometimes, divorce is better for the kids. This is assuming that there is a high level of conflict due to marital unhappiness.
Bauserman, R. (2002). Child adjustment in joint-custody versus sole-custody arrangements: A meta-analytic review. Journal of Family Psychology, 16(1), 91-102. Retrieved March 1, 2006, from EBSCOhost database.
Gunnoe, M., & Braver, S. (2001). The effects of joint legal custody on mothers, fathers, and children controlling for factors that predispose a sole maternal versus joint legal award. Law and Human Behavior, 25(1), 25-43. Retrieved March 1, 2006, from JSTOR database.
Thwaite, J., Silitsky, D, & Luchow, A. (1998). Children of divorce: Adjustment, parental conflict, custody, remarriage, and recommendations for clinicians. New York: Jason Aronson, Inc.