It's quite simple really, you get MARRIED. This change of life status event makes your new spouse a legally eligible dependent that you can add onto your coverage at your employer or to your individual health insurance policy. You have 60-days after getting married to make this change to your coverage.
If you are covered by employer based coverage you can double check on this with your personnel department. While I've never seen it in my nearly 30 years in the business, there may be some self-insured employer out there that has established an internal personnel policy that allows for the coverage of "boyfriends" and "girlfriends". But these more casual relationships do not have the same legal recognition that establishes a true dependent status such as with a husband, wife or children. It is highly unlikely that your state's insurance regulations and/or your employer's personnel policies will confer true dependent status on this level of relationship.
If you are covered by employer based coverage you can double check on this with your personnel department. While I've never seen it in my nearly 30 years in the business, there may be some self-insured employer out there that has established an internal personnel policy that allows for the coverage of "boyfriends" and "girlfriends". But these more casual relationships do not have the same legal recognition that establishes a true dependent status such as with a husband, wife or children. It is highly unlikely that your state's insurance regulations and/or your employer's personnel policies will confer true dependent status on this level of relationship.