Under the Illinois Marriage and Dissolution of Marriage Act Section 602(b), the Court cannot consider the conduct of a potential custodial parent that does not the relationship with the child. See In re Marriage of Radae, 208 Ill. App. 3d 1027, 1030 (5th Dist. 1991).
As a general rule, a parent’s sexual relationship with another person does not disqualify a parent from being awarded custody so long as the sexual conduct does not take place in the presence of the child and does not otherwise affect the parent’s ability to appropriately parent the child. Unspecified moral indiscretions, while troubling, are generally not enough to award custody to the other parent. In fact, the accusatory parent may even appear over reactionary, and his or her efforts to protect the child may backfire. See In re Marriage of Craig, 326 Ill. App. 3d. App. 320 (3rd Dist. 1993).
Conduct that can be shown to somehow affect the mental or physical health of the child, such as drug use or violence or abuse, whether or not it takes place in front of the child, may very well disqualify a parent for being a custodian. For instance, the court in In re Custody of Williams, 104 Ill. App. 3d 16 (3rd Dist. 1982), refused to ignore the domestic violence committed against wife by husband even though it occurred outside of the presence of the child. The abuse was significant in determining the best interest of the child even though it was not committed against the child or in his presence.
Often parents will think that because the other parent has been a “bad” spouse or uninvolved parent, the court will try to shield the child from that parent. The opposite is generally true. The court is inclined to maximum the involvement of both parents absent any clear and convincing evidence that there is a serious endangerment to the child. The parent who promotes a relationship with both parents will most likely to be awarded custody in any custody dispute.