As we can see in the Season 2 ending, Jake in One Of Us Is Lying went to a Rehab center for the treatment of sociopathic behavior. 

He admitted that he lied about going to Greece and he was not involved in this Tech savvy using “About That” to threaten everyone because he was in rehab all along.

DmTalkies reports he went to Wild Awakenings rehab center, the same center where Andy's mother was referred. During the conversation with Vanessa, Jake revealed that he went to the treatment at the rehab center instead of traveling to Greece for the Summer Holidays. Addy had a relationship with Jake for quite a while. However, Jake is very manipulative/controlling in the relationship and dislikes liars and cheaters. 

Jake met two women in Wild Awakenings. The first woman was compulsive liar Giselle Ward, and the other was the impulsive psychopath Fiona Jennings. Fiona had stabbed her math instructor, Mr. Sheridan.

Addy believed that Jake was breaking things up with her because he had been away in Greece all summer, and she began having an affair with TJ. Eventually, Jake discovered that Addy was cheating on him, and he was caught red-handed. However, Simon had already warned Jake about it. 

Finally, Jake and Addy parted ways. Despite wanting to get back together with his ex-girlfriend Addy, Jake was upset that she had lied to him. In the previous episode, "One of Us Is Dead," Jake hosted a Halloween party and dressed as a magician. Despite her interests, He wanted Addy to dress as a cat. 

When Addy was riding her bike, Jake chased her in his car. He drove after her off the road with the intention of killing her.