Kind of sad that only one of the love interest guys was (potentially) forgiven considering that like.. they WERE all under magic mind control.
Ehhh, in the confrontation scene, only Erin looked even regretful about the circumstances, all the other fiancees seemed to be detached from their engagements. (Plus; they all (except for Erin) took time to have a jab at their (ex)fiance lol)
Secondarily, Erin and Henry's relationship was built up as something mutual, and enjoyed by both sides, but we don't know if any of the fiancees actually desired their engagements like Erin did. And even if the beginning was good, I wouldn't want to stay in a relationship where I got cheated on constantly and publicly (and if Henry's behavior is like the other's, probably verbally harassed). The fiancees got given a (likely rare) route out and they took it.
tldr; mind controlled or not, the male leads hurt people. You're never obligated to forgive the one who hurt you, and the fiancees didn't. Erin might though, and that's ok too!