Well, there's the Metropolitan Community Church, for a start. Christian church established by the gay community some years ago, now international.
DW and I wouldn't want to be married anywhere we weren't welcome.
The marriage for procreation thing though... First, that means that when my widowed granny remarried in church in her 70s she was doing it under false pretences. Second, since my friend knew she was infertile when she got married in a cathedral, she shouldn't have done it either. Tut.
As for Adam and Eve, looking at most of the partnerships in the OT - Leah tricked Jacob into marriage, Rebecca egged her son on to lie to his dad, Delilah cut Samson's hair - and Adam and Eve just seemed to want to drop each other in shit with God - I'd take David and Jonathan or Naomi and Ruth any day.