How did Chillingworth account for the way everything had happened?

Chillingworth insists that his revenge and Hester’s silence are “[their] fate.” “Let the black flower blossom as it may!” he exclaims to her. “Now go thy ways, and deal as thou wilt with yonder man.”

Chillingworth actually thinks he was helping Dimmesdale. It is an example of his own twisted self-delusion,

“What evil have I done the man?” asked Roger Chillingworth again. “I tell thee, Hester Prynne, the richest fee that ever physician earned from monarch could not have bought such care as I have wasted on this miserable priest!

He says that he could have exposed the priest and saved him from the gallows. Hester points out that the gallows would have been much kinder than the slow torture Chillingworth put him through. Chillingworth shows no remorse nor understanding of his actions. He is a jilted lover who found solace in the torture of another man's soul.