Retroactive jealousy is the irrational fixation on a partner's past relationships or experiences, even those that predate the current relationship. It's less about logic and more about the nervous system's response to perceived emotional threat, explains relationship coach Andrea Tan.

One couple's 13-year relationship suffered until they identified the problem. Private tutor Robert Chua says his ex-girlfriend's retroactive jealousy eventually led to his isolation and the end of their relationship.

Couples and trauma therapist Tan Yi Shan says attachment wounds from childhood or past relationships can make someone feel threatened by their partner's past. Social media often acts as a trigger, allowing one partner to 'dig up' information about the other's history.

Chua says he stopped contacting friends, male and female, to avoid triggering his partner's insecurities. 'I realised that whenever we fought, I had no one else in my life to speak to,' he says.

Experts say addressing the problem requires self-awareness and communication. They suggest focusing on how the current dynamic affects both partners, not on assigning blame. Simple neurotherapy exercises, like side-to-side eye movements, can help break the cycle of fixation.

The goal is not to eliminate jealousy but to build a healthy awareness of each partner's needs. 'It's less about powering through intrusive thoughts, and more about addressing the mental beliefs and anxiety around uncertainty and doubt,' says Andrea Tan.