Seven Moves by Carol Anshaw

This second novel from Carol Anshaw, author of Aquamarine, describes a desperate search for a lover who has simply disappeared one morning without a trace, and a gnawing fear that perhaps the lover was not really known at all. Chris is a therapist in a stable and strong lesbian relationship with Taylor, a travel photographer and a free spirit who has occasionally been unfaithful. When Chris awakens to find Taylor gone she cannot accept either suicide or abandonment as explanations. She hires a cop, a private investigator, and a psychic and goes looking for Taylor, a journey in time and place, across the world, and back through memory. The pursuit becomes an investigation of what we can know about another.