You will most likely know your partner's scent.
While this can definitely be the case, particularly with people who know they will find it painful to see an ex that they may still harbor feelings for, it is also common for exes simply to move on in a manner that leaves the other partner behind.
After all, who does not want to look their best for the person they are feeling attracted to? It never hurts to consult a mental health professional, including those here at , for guidance and advice when in doubt.