When Did You Know She Was "The One"?

The question was, Married men of Reddit: what moment with your future wife made you think "Yup, I'm asking this girl to marry me."? The thread is full of love stories that show how consideration and self-sacrifice mean so much more than looks, money, or fun. Sully1102's story is touching.

Things were going really well, and I was saying to myself "If this keeps up, I think next summer I'll pop the question."
Then, my mother had a stroke. We were all sitting in the waiting area outside the ICU, because only 2 people were allowed in at a time. It was my now-wife's birthday, and a Wednesday, and she didn't hesitate to take the day off to sit with me and my family.
I went to visit my father at home, and she came with me. Her Italian instincts kicked it, and she brought a load of groceries and a lasagna with her.
My father was a mess at the hospital, and it fell on me and my siblings to speak with the doctors and make plans.
I would get home, and pour myself some bourbon. She made me dinner, and just sat with me while I silently sobbed.
It wasn't about how great we were when things were good, it was about how perfect she was when things were bad.
I bought the ring 2 months later.

Danger0clock had a short but meaningful story.

The day she took off work to help me go through a dumpster. I had accidentally thrown my keys in the trash while cleaning out my car.

Yeah, they found the keys, but it took a couple of hours. There are plenty of other stories in the thread, and also at Metafilter.