I'm not married. We've been together for nearly 15 years and have a 13 year old daughter.
Neither of us were bothered with the idea of being married, for my part because I hate the idea of being "in the spotlight" all day, and because my family would pitch a fit if we did the registry office thing.
The financial stuff bothers me, but not due to my own risk. I bought the house prior to us getting together, I have the full time well paying job whereas she's done the child care and works 2 - 3 days a week at minimum wage. I have the bulk of savings due to inheritances. We both have access to each others current accounts, but tend to stick to our own. Pretty much all household expenses come out of mine, with the absense of her phone bill and the occasional supermarket shop. We probably have about the same amount of spending money at the end of each month.
Wills are sorted, so if I die, it all goes to her, but I worry about how she'll cope if ever we split up.
I know that I should make things more equitable, but I'm completely unwilling to due to her money sink of a sister. She won't work, and is slowly draining their father of all his money. My partner has lent her so much money over the years and never gets it back. The pair of them inherited a house 3 years ago, which is still sitting empty because her sister refuses to sell because she wants to live in it, but has no money to do it up to make it livable. Trying to get my partner to deal with that is the only thing thats come close to splitting us up, so now it sits shoved under the rug, never to be spoken about again.
So we carry on as we are, she knows I don't trust her with our finances, so we live with the status quo. If we ever split up, I'd like to think that we'd be OK and we'd split things evely, but who knows, relationships don't exactly tend to end amicably.