The "custodial parent" is the contact person. However, if your settlement agreement states that you share custody (meaning you have visitation rights, the right to join in decisions regarding the child's health, education, etc.), then you make such decisions JOINTLY. Just because your child lives with your ex-wife (which is what usually happens in a divorce), you have rights as well, especially visitation rights. You must abide by the settlement agreement, but if your circumstances change (like losing your job), you need to petition the court based on "a change in circumstances." I hope I answered your primary question.