Is there a “marriage premium” for gay men?

Data on cohabitation suggest that the answer is no, whether for gay men or cohabiting heterosexuals.  The standard selection story is that women are more likely to choose the high earning men and marry them.  But why don’t women live with these men too?  Does living together not transfer enough resources?  Could it be that real legal marriage is proxying for the ability to commit, which is positively correlated which other determinants of job success?