Tony couldn't believe his life was actually improving. After Ziva left him, his heart was shattered in pieces like broken glass. He thought he was never going to be happy again. Every time he went home to his goldfishes, it was a reminder of his loss, after all one of the fishes was named "Ziva". For the first couple of months, he was devastated; he wasn't sleeping, he wasn't eating, he didn't wanna make jokes. When he opened his desk drawer at NCIS, his heart skipped a beat because of Ziva's necklace: the "present" she gave him back in Israel.
The squad was very worried about Tony; even Gibbs showed a little concern for the very special agent. He would sit and his desk hours after a case and stare at what used to be Ziva's space. He didn't talk or move at all; he only looked at the desk with very heavy eyes. Days passed, then weeks, months and, finally, a year…
Tony was starting to get back in his feet. Gibbs hired ex-CIA analyst Ellie Bishop and people started moving on. Nobody forgot Ziva, – especially Tony – but after sometime you gotta move on. The hole in his heart was starting to heal. Fate, destiny, coincidence or however you wanna call it, decided it was time for agent DiNozzo to get back out there and give love another try. He bumped into Zoe Keats, now and ATF agent, during a case. Many years ago, Tony left and didn't say goodbye to her. Now, it was his chance to set things right and make emends.
They started dating, had some fights – especially because of Tony's commitment problems – but when he had to Irak following a lead on The Calling, everything was great between them, no buts.