I bet later in the story The Boss tries to bury MC's sister through some kind of civil case. If you haven't dumped her, I bet it leads to you convincing Nicole to take leave from work, come to Sunshine Bay, and represent MC's sister in the case with you. And afterwards, if you choose to stay with her, maybe you and her agree to sell the apartment, she quits her job, and the sister hires Nicole to be counsel for the hotel. And... maybe if you dumped her, The Boss hires Nicole's firm, and she ends up working against you instead, albeit reluctantly. Oh the drama...