The father of my child is living with his to other children and their mother, yet he is paying $450 a month in child support for those children.

He has an obligation to support his children.  He has the right to deduct for the costs if the children do not live with him, and he is ordered to pay child support, or one half of the amount he would be required to pay if they do live him and he were not required to pay child support.  The statutes are as follows: 518.29 (g) provides: Child support or spousal maintenance payments ordered by a court for a nonjoint child or former spouse or ordered payable to the other party as part of the current proceeding are deducted from other periodic payments received by a party for purposes of determining gross income.   518.33 provides,    (a) When either or both parents are legally responsible for a nonjoint child, a deduction for this obligation shall be calculated under this section if:  (1) the nonjoint child primarily resides in the parent's household; and(2) the parent is not obligated to pay basic child support for the nonjoint child to the other parent or a legal custodian of the child under an existing child support order.  I think it is a reach to say that it is fraud for him to pay child support for children who live with him.  The adjustment should be taken into consideration in your child support order.