No Other Love

Description for NO OTHER LOVE by Flora Speer:

VISION OF DESIRE
Only Herne saw the woman. To the other explorers of the ruined city she remained unseen, unknown. But in the dead of night she beckoned Herne to an illicit joining with the words, 'I am your fate. Accept it, for there is no breaking the threads spun before time began.'

With the dawn's light she was gone, but Herne found he could not forget his beautiful seductress, or ignore her uncanny resemblance to another member of the exploration party. Cool and reserved, Merin could pass for the enchantress's double, except for her touch-me-not manner. Determined to unravel the puzzle and to penetrate Merin's protective shell, Herne began a seduction of his own, one that would unleash a whirlwind of danger and desire.

This is #3 in Tales Of Dulan's Planet.