Henry always avoids talking about his past, in large part because he spent some time in prison. when his fiancé´, carla, finds out about it, she is horrified an
I believe the correct answer is: omission.
Omission is a term which is used for someone or something that has been left out, excluded or the action of excluding or leaving out someone or something. In this case, Henry is leaving out the fact that he spent some time in jail, for which his fiancé´, Carla, is accusing him of deception by omission.