Tony was having a hard time deciphering why was was doing what it was he was doing. Ziva David, Mossad liason officer, was his partner. Four years together, on the job. Four years of working together and trusting each other with each other's lives. Four years of watching her change from a killing machine to an investigator. Four years of watching her grow from an emotionless officer to a woman with a heart.

Those four years held so many memories. Their first undercover mission as married assassins. Being trapped inside a shipping container. Chasing bad guys. Interrogating together. Gibbs nearly dying, then retiring for four months… Leading the team. Gibbs coming back to save her. The undercover operation with Jeanne Benoit . Keeping secrets. Nearly being blown up. Revealing secrets. Being confronted by her in the men's restroom. Conversations about soulmates… or lack thereof. Jenny's death. Being an agent afloat for four months. Not calling her. Seeing her again. Learning to be normal again. Going home.

Things never felt quite right after that, and he couldn't figure out why. She became increasingly withdrawn. And then she went back to Tel Aviv… Everything had changed. Her old wall, the one she had put up around her heart time and time again, whenever someone got too close… It was up again.

When he first found the picture of Rivkin on her desk, he surprised even himself. The old Tony would have immediately used it as blackmail, bugged her about it, or, if he had really wanted her, he would have done everything in his power to get her, no matter the cost. He would have made things miserable for her if it didn't work out. But that day, things were different.

That day he decided her happiness was worth more to him. Something inside him to him to put her before himself, to let he be happy.

He wasn't quite sure what it was.

He had never wanted to kill Rivkin, not out of jealousy, anyway. But if he hadn't, then he would be dead. Rivkin would still be playing Ziva, and it would get her hurt, maybe even killed. So that night, as he went home, he didn't regret killing Rivkin. He didn't regret protecting her. He only regretted letting her get hurt.

She was worth it. He didn't know what it was in him that told him this. He didn't know what it was that made it okay.

All he knew is that he did it all for her.