what theory applies best to this case? Cognitive therapy, behaviorism (operant and classical conditioning), psychoanalytic theory, existential/ humanistic theory

Anna felt that she was doing everything to keep the relationship going, and that Brian took her for granted. Brian felt isolated and neglected, and often found himself lacking the motivation to do the things he felt Anna nagged him to do. Anna was thirty and worked full time as a personal assistant while completing a Master's degree part-time in the evenings. Brian was also thirty and had completed his degree. Since graduating five years ago, he had held a variety of temporary jobs and was unemployed when the couple first scheduled an appointment with you. Although she wished Brian would put efforts into finding a job, Anna noticed that he spent most of his day playing video games. The couple were engaged to be married, and had set a date for their wedding six months from now. Growing up, Anna was the eldest of four children. Her father died suddenly of a heart attack when Anna was twelve, and her mother became depressed following his death. Anna looked after her younger siblings, and was responsible for completing the majority of the household chores. She worked very hard academically because she saw this as a way to eventually support her family financially. Brian was raised by a single mother. He had no ongoing relationship with his father, who left when Brian was one. He was close to his mother when he was little, but as he grew up his mother had to spend more time working outside of their home in order to support them both. She trained as a nurse and did shift work. Brian was often left to fend for himself in the house while his mother was working.