From the comments: Problem was that since it was only roughly the same time, and not the actual same time, his Mom’s egg was fertilized differently. He’s going to return to a timeline and body that is very different than when he left.
Shane is Will’s best friend. Shane’s wife, Alicia, is Will’s worst enemy, an entitled brat who doesn’t realize how lucky she has it. After chancing upon a magical being who grants Will a body swapping spell, he takes over Alicia’s life, vowing to be a better wife and lover — and just all around person — than Alicia ever was in Let Me Stay, available on Smashwords and Amazon.