Actually, you can have same-sex marriage in any European country.
According to various Christian doctrines, marriage is a sacrament given to each other only by those who are getting maried. So you can give a sacrament to your lover, as your private matter, wear ring- as this is your private matter also, then sign a contract to set a civil partnership, give all your assets to the company, and after one's death you can inherit without any tax. There are some other issues, such as access to medical information, but this can be solved that way or another.
The problem is mainly because states tend to put their fingers to everything, including private matters, we got used to it, and we try to force everyone to do the way we want, through the state, via elections and referendums.