No. A boyfriend or girlfriend does not meet the legal criteria for being considered an eligible dependent (you can imagine how complicated that could get in some people's lives). Legally married spouses are still generally considered eligible dependents though that coverage option is evolving rapidly due to a quirk in the health care reform law that does not define spouses as dependents. Natural born and step-children and individuals for which a person has a court order appointing them as legal guardian also qualify as dependents.
I'm afraid you'll have to get married if you want to get covered under your boyfriend's health insurance.
I'm afraid you'll have to get married if you want to get covered under your boyfriend's health insurance.