This movie makes it as if she did die after getting stabbed. Maria Bello would be the son's stepmother. Rick would remarry between films since 2 and 3 are 13 years apart by timeline, nah mean?
shareOR, this movie is an alternate Universe, while in the Universe of the first two movies, Rick and Evy did the most rational thing: stop looking for trouble, settle down, and have more kids.
How you can make the world a better place:
Don't shop at Wal-Mart.
It would have been good if they'd have known at that point that Rachel Weiz was not returning for the third movie but they didn't so they had no way of planning ahead.
"I'm smart and you're a potato head!!!" ~The Doctor