If I am afflicted with a calamity, then I praise Allah four times:
(1) I praise him that it was not worse than it was.
(2) I praise him when he provides me with patience to bear it.
(3) I praise him when he guides me to supplicate appropriately and hoping for reward.
(4) I praise him for not making it a calamity in my religion (i.e. making one a kaafir).
[Shuraih Source: Siyar a’laam an-Nubula (Vol. 4, Page 105)]
Of course, people in our lives are a test. Parents for example, are tested with their children; Couples are tested with each other; Friends are tested with friends; etc. We are always being tested with something. It's called a test because it puts us in a position of misery and humility where we have to do something
to change our situation. The way we react to the situation, the choice we make at that point, determines how strong our faith is in Allah because we are at a place where no one can aid us but Allah subhanahu wa ta'ala. Do we drown ourselves into sin, or do we seek Allah's help? And if we choose the latter, how long are we able to sustain our efforts? How is it expressed externally? Because there is a verse in the Quran that says "Fa Usburu sabrun jameel" which means "Be patient with a beautiful patience
" and what "beautiful patience" means is to express content and normalcy as if you are not afflicted with anything even though you are torn up inside.
She chose to stay with her husband for the sake of her kids. Has she been able to see the good in her choice? Are her kids healthy? Are they happy? Were they raised better than had she been divorced from her husband? Has the marriage with her abusive husband made her a stronger person? (eg. given her insight for a better future, given her patience, made her call on Allah more often etc.). Whatever her reason was, she stayed with her husband because it was a better choice at that time for her and her children than had she left him. Even though the situation was not perfect/ideal, there had to have been some good in it for her to have remained.