Tituba was the one who led Mary to believe he had died during the war, she lied and told Increase Mather he was a witch under torture, was jealous of his relationship with Mary, had kidnapped him and planned to use him against Mary, she seduced him leading to them having sex, John hates her because she is a witch, John is no longer her captive as he was freed by Mary.
During the first season Tituba and John had little interaction with each other though she often conspires with the elders to rid Salem of John Alden as they believed that he was a distraction to Mary and ultimately was the one that had him arrested and charged with witchcraft and treason. Tituba often displays jealousy over his relationship with Mary and finally during season two after her relationship with Mary falls apart with the discovery that she kept the existence of their son a secret, she kidnaps him so she can use him to have a hold over Mary and win the witch war.
Not much is known of their early history but it is presumed that they knew each other since childhood. Tituba also knew of his relationship with her mistress Mary Walcott and was the one that turned her into a witch helping her sacrifice his unborn child to Kanyma when he went to war. It was later revealed she was the one that told Mary that he had died allowing her to marry George Sibley.
Throughout The Salem Series
In The Vow it was revealed that Tituba was the one that led Mary to believe that John had died.
In Survivors Tituba visits John and reveals that she saw his earlier encounter with Hooke and misleads him into thinking that he is blackmailing her mistress by telling the selectman that she is having an affair with John and pleads with him to put a stop to Hooke.
In Lies Tituba under the request of the elders summons the spirit of William Hooke to discover John's secrete to drive him out of Salem but uses it to her own advantage to blackmail Mary.
In The House of Pain After hours of torture at the hands of Increase Mather she tells Increase that John Alden is a witch and the one leading them leading to his arrest for witchcraft.
In Ashes Ashes John's murderous act is revealed during his trial revealing that Tituba has told Increase during her torture.
In Ill Met by Moonlight having ingested the eyes of the seer following his death Tituba discovers the identity of the witch hunter and captures John when he breaks into the home of Anne Hale with the intent of killing her.
In The Beckoning Fair One John wakes up to find himself in a mysterious room tied up by rope and chains by his wrists and ankles. Sensing he is not alone he asks where he is and Tituba ominisously replies telling him he is both inside and outside of Salem. She seems intrigued by the markings on his flesh and traces them with her fingertips. She states there is much magic on his flesh revealing that he is becoming what he hunts. She asks if the medicine man warned him of the consequences for binding his soul to the great spirit and that his own dogs would tear him apart but John tells her he is his own dog and hunts on his own, that he will see all witches burn and she proceeds to tell him she has no problem with that as long as they are the right witches. He proceeds to ask why she saved Anne Hale from him but she replies that she didn't save Anne she was saving him from her.
Later she visits John again and tells him that they we're both born free and yet have ended up slaves to the same woman but John is adamant that he is not any longer but Tituba replies that Mary Sibley would be dead if that we're true. John asks her what she wants from him and she reveals her plan to use him to have a hold over Mary and win the witch war.
In Wages of Sin Tituba reveals to Mary that John is alive to save her own life and takes her to the blood chamber where she has kept him captive. She witness as Mary admits of the existence of their son and that the Essex's witches plan to kill him, she tries to stop Mary from freeing him revealing he is the witch hunter, stating he is no longer the man she loved or once knew and that he will kill them both but she frees him anyway. Tituba is later seen tied up in John's place.