Custody and visitation is always governed by what is the best interests of the children. The best interests of the children are usually determined by a two-prong test. One, who has been the parent doing all the heavy lifting in the recent past? Johnny come lately to the parenting program doesn’t qualify you as the custodial parent. Secondly, which parent is most likely to be able to continue to provide the emotional and physical support that they have been providing for the children during the last several years of the marriage.