Tax Equity for Domestic Partner and Health Plan Beneficiaries Act - Amends the Internal Revenue Code to: (1) extend the exclusion from gross income for employer-provided health care coverage to certain eligible beneficiaries and their dependent children; (2) revise the definition of "dependent" for purposes of the tax deductions for the health insurance costs of self-employed individuals and for contributions to health savings accounts; and (3) extend voluntary employees' beneficiary association sick and accident benefits to eligible beneficiaries and their dependents. Directs the Secretary of the Treasury to issue guidance on reimbursements of medical expenses from flexible spending and health reimbursement arrangements.