In 'Part-Time Lover,' Stevie Wonder explores themes of infidelity and secret relationships. The song tells the story of a man involved in a clandestine love affair, sneaking around with his lover while trying to avoid detection by his partner. It's a tale of double lives and the complexities of forbidden love. Wonder's soulful delivery and catchy melody make this a poignant commentary on the moral ambiguities surrounding love and desire. Key moments in the song include the vivid descriptions of secret meetings and coded phone calls that highlight the lengths to which the characters go to maintain their affair.