Who approaches Dimmesdale as he invites Pearl and Hester to join him near the scaffold? Does this person want him to go on the scaffold?

Chillingworth approaches Dimmesdale as moves towards the scaffold.  Dimmesdale is moving to confess, but Chillingworth tries to stop him.  Chillingworth knows that if Dimmesdale confesses, then his revenge will be over.  Chillingworth has based his whole life since he discovered Hester's adultery, on finding and torturing Hester's adulterous partner.  Now that Dimmesdale is going to confess, Chillingworth will no longer be able to torture him.  Chillingworth will have no reason to live any longer.