Vows: I will or I do?

Last week, someone at work was saying that he couldn't understand how some people could hate their job so much, yet they don't want to find something else. "We have such a luxury in this country. I mean, if you're a slave, you can't just say, 'hey I don't like it here, I think I won't come in tomorrow.'"
I wonder if I'm like that. I don't always have the greatest time at work, but I still think it's generally a good experience.
But then he went over the edge. "It's kind of like this. I hate it when people say they should stay in their marriage for the children. I mean, the kids are going to know anyway. If you're not happy with your situation, you should find a situation where you are happy."
Wow. Turns out I've had my thinking backwards all this time! Here I thought that a good reason to stay in a marriage was the fact that you are committed to that person. And to the children. Irrespective of how well you seem to be getting along with them at the time.
If your partner lost an arm or a leg or half a face, and suddenly you couldn't do so many things that you wanted to do in life because of the partner's needs, what would you do? Would you leave them in order to pursue your own endeavours or could you say 'I love you and I'm committed to you.' Whether they are whole or not; whether they get old or not. And by the way, they will. What would you expect your partner to do if you were mangled in an auto wreck?
What's the point getting married if you know you're not committed from the start? If you're not committed your vow means nothing and you're pretty much merely boyfriend and girlfriend.

On an unrelated note, a question came to my mind today which I've argued with someone before yet realize I don't know the answer. Is it worse to have girls in your life who like you but none of whom are a good match, or to have nobody like you at all? Assuming that option three - living happily ever after - is not on the table in the hypothetical present situation.