Dreaming about attending a family reunion, especially in a familiar setting like your grandparents' house, often symbolizes a desire for connection and belonging. The presence of your ex and their new partner could represent unresolved feelings or a need to reconcile aspects of your past.

This dream might indicate that you are processing your feelings about your past relationship and how it fits into your current life. It could also suggest that you are reflecting on family dynamics and how they affect your relationships.

Consider what emotions you felt during the dream. Were you happy, anxious, or indifferent? This can give you clues about how you truly feel about these relationships. If you felt uneasy, it might be beneficial to explore any lingering feelings or issues related to your ex.

Overall, this dream could be encouraging you to embrace your past experiences and find closure, while also reminding you of the importance of family connections.