She established relationship for her needs (sexual dissatisfaction from relatively old husband). You entered for a fun. In the process you developed an emotional attachment. She doesnâ€™t seem to be that emotional for you but at the same time doesnâ€™t want to loose you. Now ride is about to get over as they are shifting. Accept this bitter fact. Forgetting is an automatic process. Once you stop meeting her and develop other meaningful relationship, you will forget her.