Sexual role playing occur when you and your partner assume imaginary identities to derive sexual gratification - for instance, a teacher and a schoolgirl, or a dominatrix and her victim. Props and costumes are often used to create realistic scenarios. Role playing is also integral in cybersex, where two or more anonymous parties pretend to have sexual relations over the internet through explicit sexual messages, or the use of graphical representations such as avatars in a software environment.
One of the possible reasons why your partner is losing interest in sex may be due to self-consciousness, or a low self-esteem. Likely causes may be perceived age (feeling old), loss of hair or even bad experiences at work, leaving your partner feeling unattractive, anxious or lacking in confidence. You can help by focusing on his /her strengths and reassuring your partner either verbally or through acts such as preparing a nice meal or buying gifts.