Why is mrs keeney on the ship how does this information influence your opinion about the conflict between the captain and his wife

According to the Steward, Captain Keeney refuses to turn back because he is determined to get more oil first. Mrs. Keeney, as described in the stage directions when she first appears is nervous, unhappy, and submissive. Mrs. Keeney admits to her husband that she expected to enjoy the voyage, but instead she feels like a prisoner. Mrs. Keeney sees that her husband is a hard man who can be brutal toward his crew in pursuit of his goal. Keeney's pride pushes him to put his goal of getting the oil ahead of any feelings for his wife. He needs to get the oil to feel strong and to prove himself. At the same time, he denies that his wife is really going mad because he can't believe she is actually losing her mind and because she insisted on making the voyage in the first place.