That' does not answer the question.
You said...
Marriage is an agreement between people, a type of commitment to support each other emotionally, to plan the future together, and to share life's moments. In addition, you can let the government know and get an actual license that says you are married.
In addition is what you are mentioning that you said, but I asked you about your description of what marriage is. So @Earthtank is right then... you made it up?
No, I use the current definition: I am married because I have a signed marriage license. That is what it *means* to be married.
Now, what it means to be *committed* is another story. And my wife and are *are* committed to each other (as she is to her other partner). But we are not *exclusive* with each other. There is a huge difference.
Ultimately, to be married is to have societal approval of the romantic relationship you have with someone else.