How does the appearance of Quint (the late valet worker) and Miss Jessel impact the current governess as the story progresses?

Peter Quint is one of two ghosts who the governess claims is trying to corrupt Miles and Flora. The governess is the only one who claims directly to have seen the ghost of Quint, which appears to her several times throughout the story. The first time he appears, the governess mistakes him for an intruder. After his second appearance, the governess's description to the housekeeper marks him as Quint. The housekeeper tells her that Quint was the former valet and was a vile man when he was alive. He had an affair with Miss Jessel, the previous governess, even though he was a servant and she belonged to a higher class. According to Mrs. Grose, Quint had suspicious relations with Miles while still living.