Historically, marriage has either been an actual/implied contract–binding human beings and their offspring within certain legal parameters–or a religious/spiritual sacrament, acknowledging the metaphysical bond and personal devotion between two people within their own set of religious/spiritual beliefs.
The time is long overdue for governments at all levels to get out of the business of marriage certification and oversight.
Let all who wish to be married within their own religion or according to their own belief systems do so.
If their religion does not support same-sex marriage, let them work within that organization to change the rules, or find another which will.
As for the legal issues which currently inspire many to enter wedlock, let those rules be either stricken from our laws or rewritten so as to erase the requirement for wedlock in certain circumstances.
Give any and every person the right to designate one person as their significant other or “spouse”.
Let this designation fulfill the requirements for such things as the ability to visit a loved one in hospitals, inherit estates as a “spouse”, qualify for certain benefits or be a confidant who cannot be compelled to testify against the other in court.
Children would continue to be protected by support laws and protection services.
Of course, many benefits (both private and public) might be abolished, but that would only serve to give equal rights to “single” people…