I don't really believe this to be relevent, because you can't become an expert by being married once- then you're only an expert in YOUR marriage, not in other people's.  And if you've been married a few times, then I guess you're no expert anyway.  But as you asked:

I am not married- I don't believe that two people need a piece of paper to show commitment.

I am 30 years old, straight, and in that time I have had two long term relationships.  In between the two I tried free love too.

So seeing as you wanted me to tell, how about you?  I'm guessing you entered a relationship/got married young, and are still with that woman/man... something like that, because otherwise I doubt you'd be asking.