Jens Larssen

In the Harry Turtledove series, WorldWar, Jens Larssen is a nuclear physicist working on the Manhatten Project. When he goes missing and is presumed dead, his wife begins a relationship with another man. When Jens returns, he finds his wife pregnant with another man's child. Unable to take the strain, Jens tries to defect to the Lizards, but is killed in the attempt.