What was the past relationship between John Proctor and Abigail Williams?

Abigail Williams and John Proctor had an adulterous affair when Abigail was a servant in the Proctor household. This past relationship was discovered and became public knowledge, damaging Proctor's reputation and leading him to be accused of witchcraft later in the play. Abigail's desire to reclaim the forbidden relationship played a significant role in her accusation against John Proctor during the Salem witch trials.