I'm pretty sure that might be referring to sharing her with her son/ your friend. I personally want to keep her for myself, so I choose the solo route. You would have to go back to when you become friends with him, and they give you a choice to either tell him the truth or lie to him about what you've been doing with his mother. If you pick to tell him the truth, it will put you on the friendship path, and you will share her, I believe.