The IRS is loath to get involved in custody and marital issues. It is IRS policy to recognize a custodial parent as the parent that is entitled to claim and deductions or credits that pertain to the child. A noncustodial parent needs a signed Form 8332 (or a written instrument including all of the information included in the IRS form) in order to claim any deductions. This form releases the custodial parent’s right to the exemption to the noncustodial parent. Without the form, the IRS can rightly reject the claim.
While you are entitled to claim an exemption for your child, you are ineligible to claim head-of-household status. You fail to meet the requirements because your child does not live with you for more than half the year.