Dreams involving past relationships can often reflect unresolved feelings or a desire for closure. In your dream, the Halloween setting suggests themes of transformation and change, as Halloween is often associated with masks and hidden truths. The act of sifting through candy might symbolize sifting through memories or emotions related to your past with your ex-husband.

The presence of your brother-in-law and sister-in-law could indicate a connection to family dynamics and how they influence your feelings about your past relationship. The newborn baby boy symbolizes new beginnings and the potential for nurturing and growth, perhaps signifying a longing for a fresh start or the desire to create a family.

Your ex-husband's distant demeanor could reflect your feelings about the relationship—perhaps you feel a sense of disconnect or distance that still lingers. His comment about your ability to care for the baby so soon after giving birth might suggest that you are recognizing your strength and resilience, even amidst the complexities of your past.

The mention of him taking an assistant coaching job could symbolize his pursuit of new opportunities and personal growth, while also indicating a contrast to your own situation. Overall, this dream may be highlighting your feelings of nostalgia, the complexities of your past relationship, and your journey toward healing and moving forward.

Consider reflecting on what aspects of your past relationship you may still be processing and how they relate to your current life. It might also be helpful to think about what new beginnings you want to embrace moving forward.