While most people bestow the trait of manipulation upon Roger Chillingworth, the reality is that Dimmesdale can actually be just as manipulative with other aspects of his life, and that of others.
The reason why Dimmesdale may be considered manipulative has to do with his status as a minister and with his ranking in the village. Dimmesdale has managed to keep the relationship with Hester a secret. By a huge strike of luck, he happens to have sinned with a woman of dignity who is determined not to ruin his life or reputation. Moreover, on her own accord, she has decided to not betray the secret that brings them together.
Dimmesdale, however, has a very subtle way to manipulate, and it is by continuing to live the façade of being the mentor of the people, the spiritual leader of the masses, and the representative of God among all. Dimmesdale uses his presence, his looks, his intelligence, the charisma that he no doubt exudes, and his words to draw the attention of everyone. He does that quite effectively.
But even when the minister's voice grew high and commanding--when it gushed irrepressibly upward--when it assumed its utmost breadth and power, so overfilling the church as to burst its way through the solid walls, and diffuse itself in the open air--still, if the auditor listened intently, and for the purpose, he could detect the same cry of pain. What was it?
It is important for Dimmesdale to continue playing this character. It is important that the village keeps its young divine intact. It is important for the parishioners to have the hero that that they see in Dimmesdale. For this reason, even unbeknownst to him, he does manipulate with the charm and splendor that his presence causes, making everyone forgive him everything, even ignoring the confession that he makes in the end.