¶1concurring in result only, with whom TAYLOR, J., joins.
¶2I do not agree that a court may take into consideration at a custody modification hearing romantic relationships occurring prior to the original custody agreement. I agree with the majority’s resolution regarding the reopening of a joint custody decree when the parties ask the court to intervene, and concur with the result only because the record includes other sufficient evidence to support the trial court’s custody decision.
¶3When a district court signs a decree of divorce incorporating the parties’ child custody stipulation, the district court makes a finding that the custody provision is in the best interests of the child. The trial court is not bound to accept a stipulation, but rather must consider independently what custody arrangement is in the child’s best interest. See Forbes v. Forbes, 672 P.2d 428, 429 (Wyo.1983). The findings are made in the context of all surrounding circumstances regarding the parties’ lifestyles, parenting abilities and the well being of the child. When the court enters a decree awarding the parties joint custody, an assumption can be made that the court was even more thorough in its findings because joint custody presents many unique questions involving the best interests of the child. J.B. Singer & W.L. Reynolds, A Dissent on Joint Custody, 47 Md.L.Rev. 497 (1988) and E. Scott & A. Derdeyn, Rethinking Joint Custody, 45 Ohio St. L.J. 455 (1984).
¶4Here the stipulation for joint custody included representations by the parties that sharing of custody was in the best interests of the child, and those representations were made by the parties with full knowledge of each other’s history. A party, based on that representation, should be estopped from later arguing at a modification hearing that the other party should lose entitlement to joint custody because of premarriage and/or predi-vorce lifestyle. The determination at a modification of custody hearing to go back into time to revisit a party’s predivorce, and in this instance premarriage, lifestyle seems obtrusive, especially where no connection was made depicting how the premarriage lifestyle relates to the present lifestyle or parenting abilities.