The song "What Am I Doing Here With You" by Gilbert O'Sullivan expresses the narrator's confusion and frustration with his partner's doubts and accusations about his love and faithfulness. The lyrics suggest that the narrator is deeply committed to his partner and would never leave or let her down. The narrator admits that he has experienced different relationships and romantic encounters in his life, but with his current partner, things feel different and special. Despite his honesty and assurance, his partner continues to doubt his love and accuses him of loving someone else. The narrator questions his partner's lack of trust, wondering why she doubts him when he has shown nothing but loyalty and love towards her. He emphasizes that his feelings for her are genuine and asks her to explain why she believes he loves someone else. The narrator also questions the reality of the situation, suggesting that he believes it may all be a dream. He pleads with his partner to tell him what is really going on and expresses his love for her, hoping for resolution and understanding. Overall, the song portrays a relationship filled with doubt and insecurity, with the narrator desperately trying to prove his love and loyalty to his partner.