Alternatives: Alternate Reality Series — Robert P. Fitton

He's 500 years old and can create reality of his choice. Five hundred years ago, in present day Colorado, Ricardo and Martin stumble upon an alien mountain outpost called Cibola. The Aabaec change realities for Ricardo at will. In the present day, Ricardo rips Peter Sturgis from Jeannie and his children, and places him in an alternate reality, where Jeannie is a Hollywood star, Jean Carisle, married to Ricardo. Peter wins the Jeannie of this alternate reality and faces his ultimate showdown with Ricardo when Ricardo orders Jeannie's death.