The only privet pwi game i know that successfully dose gay marriages so far is AaD on the blue dragon network via Control panel it coast 500 DNVP to marry same sex you and your partner get a code. enter code of your partner and vice a verse and hay presto your married its easy can be incorporated here.
GM would have to look in to finding a way to Incorporate it here hopefully they will find a solution?
had a Female Char married to female char in AaD before coming to EpicPW