A new research paper studies how relationships change after marriage:
The belief that your partner helps you to better live up to your commitments and responsibilities was only found in more satisfied marriages ... This belief wasn’t found as important in non-marital relationships (which is not surprising, since marriage is the epitome of a commitment one can make to another person).
Why shouldn't the social, psychological and spiritual benefits of marriage be available to all, regardless of sexual orientation? Why does the right want to withhold those virtues and practices from one tiny segment of the population? To punish them?