The 'Glee' star had been dating her co-star for more than one year before he was found dead in his hotel room in Vancouver, Canada on July 13, and she opened up about their special bond after he surprised her in Beverly Hills, Los Angeles, during one of the last interviews she gave before he overdosed from heroin and alcohol.
She told Marie Claire Mexico magazine: "It's more interesting having a relationship with someone you work with because we get more attention because we play boyfriend and girlfriend on the show and we are also in real life. But he is the best person I know, he has made my life so incredible and I am so thankful for him and not only to have him as a partner but also as a co-worker."
She added: "It is important to have someone that supports you and encourage you, someone that makes you feel that you are unstoppable, that you can do anything in the world because you have him."
The 26-year-old actress appears on the cover of the magazine's August issue and Cory surprised her by showing up to support her at the photo-shoot.
Lea was enjoying a "girls' night" when she learned of Cory's death and reportedly "started screaming" after receiving the heart-breaking news.
The actress joined Cory's family at a private cremation last week to say goodbye to her boyfriend, who had been battling substance addiction on and off since he was a teenager.