Application of Tax Laws Regarding Child Support
The Colorado court MUST order that your husband is entitled to the tax dependency exemption. By Colorado statute, he and the mother would split the exemption in proportion to their repective contributions to the support of their child. Your husband could take the exemption as awarded provided that he is current in child support at the end of those specific years.
However, the ex-wife would need to fill out an IRS form consenting to your husband taking the tax dependency exemption. Otherwise, by federal tax law, the custodial parent presumptively takes the deduction.