And this will not only be the case with people posting here. People in your life, in your partner's life, and so on will have similiar expectations.
There is a lot of social pressure to formalize long-term commitment, and the assumption is always going to be that one or both of you have commitment issues if you will not do that.
Perhaps the forum rules should include "legally married only".
Now that this is creating a bias I will have to find another home.