Dreams involving family dynamics and financial exchanges can carry significant emotional weight. In your dream, your father giving money to his long-term mistress's child may symbolize feelings of betrayal, insecurity, or concerns about loyalty within your familial relationships.

This scenario could reflect your feelings about fairness and support within your family. Perhaps you are processing your thoughts on parental responsibilities or financial security. It might also indicate a fear of being overlooked or undervalued in your own life or family context.

Consider reflecting on your current relationship with your father and any feelings of competition or resentment you might have regarding family resources or attention. It could be helpful to explore these feelings further to gain clarity on their impact on your waking life.