Being loyal to one another is one of the most crucial qualities that siblings should have since it forms the basis of every close-knit relationship. In the story below, the step-sister is baffled. The original poster (OP) allowed her brother-in-law to deceive her sister for a long time. In this case, OP's sister and her partner are the proud parents of a handsome baby boy. The sister stays at home to raise the baby and her husband fulfills the financial requirements of the household. At first,…