Beth hates Jamie in Yellowstone primarily because, as teenagers, Jamie helped her get an abortion at a clinic on the Broken Rock Reservation, but he did not tell her that the procedure would also include an involuntary sterilization. This left Beth unable to have biological children, which caused her deep physical, emotional, and mental pain. This secret betrayal deeply damaged their relationship and is a core reason for her ongoing hatred. Over time, their animosity worsened, especially as Jamie walked away from the Dutton family and later started a family of his own. Additionally, Beth distrusted Jamie's loyalty to their father and the family, which further fueled her hatred. The sibling rivalry culminated tragically in season 5 with Beth killing Jamie, reflecting the intense and toxic nature of their relationship.
