The vows themselves are not binding. The marriage itself is; there is no law against infidelity. As said all you need to do, legally, to be wed is both sign a piece of paper, show ID, and not be already married. Everything else is extra and based on tradition. Tradition is not law.
I am my own. I am not defined by my relationship. It plays a big role in my life, a massive role, but it does not define me. The same way my common-law wife is not defined by me or our relationship. We don't belong to each other, we work together.
The nature of marriage is a promise that you won't stray. But a promise is not legally binding. The only thing that is legally binding is the paper you sign that says you are married and know of no reason that you legally cannot be.
Yes, but that doesn't mean that she has to be dependent on you. There's a difference between being a woman and being a slave. I'm sure you treat her well, but I'm also sure that she is not dependent on you for everything (even if she is a home-maker; she probably worked before and could again if she chose to).
In a partnership, no one is wholly dependent. You may fill different roles (should, really, as each has their own strengths to form a stronger partnership) but you'd both be equal.
I agree on that; it is a statement. But many people don't need that kind of statement. Especially not one that often costs tens of thousands of dollars.
You don't need a lawyer. It is advisable, but it is not a requirement.
I'd imagine laws on marriage are more or less the same in most of the 'western world.' I'm not saying marriage is a falsity, and I agree that it is tradition. What I'm saying is that vows and promises are not legally binding, and that not getting married does not mean that you are not committed.
[EDIT] Oh yes; Sorry for calling you a neanderthal. That was a bit over the top. And I'm happy to hear you treat your wife well.