How does she do it?

My poor wife was stricken with a stomach bug much of yesterday that meant that Daddy was the primary caretaker of the household. This is really the first time I have had to pull extended double duty of Anna and Madelyn and I was worn out. At 9 PM, I just had finished the 1 hour marathon of putting both kids to bed and cleaning up the dishes/house and I wanted to curl up in a little ball in the corner. Either kid, one on one, was no big deal. But, when I had both kids, a 3 month old and 21 month old, requiring my attention or screaming I just about lost it. How does Heather do it everyday? I decided at one point, just before giving Anna a bath then Maddie a bath before bed that I would get a picture of the three of us. I may not look it, but I am beat by the time I took this picture around 6:30.

All I can think of is that it must be a personality thing and I am all wrong for it. Maybe its just patience...or patience plus many other traits which I severely lack in. Whatever it is, a couple thoughts crossed my mind at the end of the day that I shared with Heather...
1) She deserves a raise
2) I think I need to get more life insurance out on her because I will need help more than just the working hours if, God forbid, anything ever happens to her.