The big reason for marriage these days is for tax purposes. But it really only benefits you if it's a single-income household. Dual income households usually make out worse tax-wise when married. There's also some benefit to marriage for spousal rights and the other stuff that the same-sex marriage folks fought for...
Quote: Hospital visitations Child custody rights Adoption rights Parenting rights Automatic inheritance Divorce protections Immigration law Medicaid Retirement plans Social security benefits Survivor benefits Spousal and child support Federal taxes / joint taxes Exemption from property tax upon death of a spouse Immunity from being forced to testify against one's spouse Health insurance continuation of health coverage Medical decision-making power on behalf of a spouse Standing to sue for wrongful death of a spouse Access to family insurance policies Domestic violence protections