Retroactive jealousy - a resentment towards and insecurity over a love interest or partner's past romantic experiences
What makes retroactive jealousy even worse than standard jealousy is that retroactive jealousy concerns events and feelings that have already taken place, that cannot be revisited or engaged with except in memory and recollection.
People who suffer from retroactive jealousy will experience feelings of deep depression, anger, or even nausea at the mention, thought, or reminder of their partner’s romantic and sexual history. Names, memories, and the slightest hint at their partner having ever been involved with someone else before them will trigger these feelings, and there is often nothing the partner can do or say to calm their retroactively jealous partner down.