Hii What helps is understanding what the fantasy is symbolically fulfilling for you and learning how to reduce its emotional grip rather than fighting it. In therapy, we work on separating fantasy from identity, reducing shame, managing compulsive mental loops, and strengthening conscious choice so the fantasy does not control you or interfere with relationships or self-respect. With the right therapeutic approach, people do gain clarity and peace around such concerns. Take therapy. You can connect with me on nine two six six seven two six zero six five.

You need proper counselling along with your partner. Visit a clinical psychologist for same.