why does juana follow kino on his path of life even if she disagrees with some of his choices

Juana knows how greed can take the hold of men's hearts and blind them to what is really important. When Juana tries to rid them of this evil pearl, Kino hits her.

“He said, "I am a man," and that meant certain things to Juana. It meant that he was half insane and half god.”

This was a patriarchal society and Juana had to follow her husband even though she knew he was obsessed with the pearl and putting their family in danger.