Why won't Hester name the child's father?

Hester refuses to name her accomplice because she will not cause him shame. She will bear the blame for them both.

‘Never,’ replied Hester Prynne, looking, not at Mr. Wilson, but into the deep and troubled eyes of the younger clergyman. ‘It is too deeply branded. Ye cannot take it off. And would that I might endure his agony as well as mine!’