The decision to get married is a private matter between two people; and neither party requires permission or a license, in my opinion. Of course, the state has to ensure neither individual is coerced into the arrangement (forced or child marriages) and the decision is based on mutual consent.
Removing the need to get a state licence for ‘marriage’ would allow consenting adults to sign whatever contract they want and call it marriage. People would be free to draw up contracts tailor-made for them, or to take one of the one-size-fits-all ‘marriage contracts’ that would inevitably be offered by private firms.
This rather simple step would make the whole marriage debate redundant. Any pair of consenting adults – gay, bisexual, straight, transsexual, or anything else – could agree to a contract that suits them and hold a marriage ceremony wherever would have them. (I say a pair, but there is no reason that three or four or more consenting adults should not be allowed to share their lives with each other in a private marriage, if they want.)
If two people love each other, then what is a) the issue and b) why should the state stop them? and, as a society, who are we to judge?
The religious argument, to restrict marriage, is obtuse. It is absurd to ask the state to only recognise religious ceremonies as superior to the rest of society; belief in a deity is an individual choice and should not require the blessing from the government. If a religious building wishes to restrict who can get married on its property, then fine. After all, it is private property.
But if we are to have true equal marriage, then why not take the decision away from the state and return it to individuals? The only successful argument against marriage is coercion; a marriage should be recognise on mutual consent. Love is a powerful emotion that does not require acceptance from a collective; it is a choice we make as individuals. Love cannot be forced.
Humans are free to form relationships with any other human. And it is none of the states business who we choose to love or marry.