Some of us were individual adults when we married other independent adults. There are many types of working partnerships that are all called marriages out there. Just because some of us do not wear rings, or otherwise advertise our relationships by changing our names etc… does not make our marriages any less significant to us.
I do not give other people a hard time if they are married and do not tell just because i was talking to them, or if they dont have a ring on or whatever. There are many different people, and different types of marriages that work differently for those people. Some people have open marriages, or are swingers, etc… marriage has many aspects to it, in its broadest sense its about a special partnership. My wife and I are very content being ourselves, for example i did not make her take my last name, because i respected her family i wanted her to keep her name.
One interesting historic fact that sometimes people forget, is that marriage existed long before Christianity, and was not even accepted by the Church until later on. So Christianity does not own Marriage. Even today other religions, and people of no religions get married, and not all of the vows are the same. Even coming from a liberal family, I often was surprised to learn about the diverse reality of even conventional marriages, never-mind finding out about alternative relationships! I remember the first time I realized two people of the same sex often live with each-other as a partnered couple; and realizing how that was ok because they were happy in their relationships. Other times when I was single and lonely, I found myself occasionally jealous of people in relationships, and had to deal with my negative emotions. These feelings of ignorance and jealousy are natural, I just think we should address them and be aware of the reality and what we think.
As a pagan priest, I do realize there are some conventional people that cannot understand this concept of alternative marriages, to which I can only say do what makes you happy, so long as it does not hurt others, and do not judge others by false standards.