Legal Question in Family Law in Massachusetts

Most judges won't change child support based on cohabitation. Your ex-spouses' housemate has no obligation to support your children. An argument could be made that the ex has lower expenses as a result of the cohabitation and that this reduction in expenses should be considered imputed income to the spouse. This is usually difficult to prove as you have to prove what the expenses would be without the cohabitation so the judge can determine the difference. Usually this analysis results in no difference in expenses or only minor difference. Make sure you run the child support guidelines with the imputed income included as it is likely to result in only a minimal difference in actual support and not worth returning to court.

Dear Father:

Child support is the obligation of the legally adjudicated parent, not the boyfriend or girlfriend, or any other third party. There are no circumstances I can reasonably imagine in which the third party's income or household contribution will reduce your child support obligation. Why would you even think different?