I can definately understand where you are coming in a been there-done that perspective. People are often baffled that my bf and I have been together well over a year and haven't moved in together - as if that is some major sign of committment. We figure when we are ready to live together we'll just get married. Until then, things are fine the way they are. Personally, I'd be happy if he bought the house across the street
But, back to you. Many couples do have a rule that they will only play with married couples, and often end up playing with unmarried couples on presumption that they are married because no one asks. Others prefer that a couple have been together X number of years. I don't know that there is a real way to gauge committment, as everyone's definition is their own. To apply it to someone else is a bit skewed, so all they can really do is set their comfort level and go with that. Whatever it is about your status is making them uncomfortable to a point that they choose not to play with you. At least you are being honest about the situation and that's all you really can do. As with so many other things when it comes to preferences all you can do is be honest and then be patient until you find a couple where all 4 of you are comfortable together.