I'm like your wife. Married, divorced and now living with my partner - 22yrs defacto.
Having been divorced, I've discovered that marriage takes a piece of paper to get in and a piece of paper to get out. It's all just paperwork.
Also, the fact that I'm prepared to leave a bad marriage would make my vows pointless. I find it hard to imagine vows to the effect of "I will love and cherish you till death do us part - on the proviso that you treat me with care and respect".
Having said all that, if I lived in a place which did not recognise defacto marriage, we would get married. But it would be only for the practicalities and not for the relationship value of a marriage.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.