She didn't say it when he left.
Her heart was breaking and she didn't trust her voice as he pressed his lips to her forehead. The stubble on his face brushed her skin gently, sending tiny shivers down her spine. She felt the tears well up as she closed her eyes, leaning into him. It was the first physical contact they'd had in weeks (other than a light nudge she'd given him in Central City), and the first he'd initiated since their kiss. For a moment, she let herself breathe him in and forget about what was about to happen.
He pulled back from her but remained close. She could feel his breath on her face when he whispered her name. "Felicity…"
She opened her eyes and looked into his. She'd missed this. This close proximity that should be uncomfortable (and would be with anyone else) but instead felt natural and even necessary with him. Since the day she'd found out his secret two years ago, they'd danced around each other so closely that now being near him felt like being home.
He breathed in to speak again and she stopped him. She could see in his eyes what he was about to say and she didn't want him to.
"Don't, Oliver." Her voice cracked and she had to blink rapidly to keep the tears from spilling over. "Don't say goodbye."
"Felicity." The way he said it, so soft and tender, caressing her name with such love and passion was the final breaking point. Tears slipped down her cheeks and she no longer fought them, knowing it was a losing battle now.
"Don't say it. If you say it, it sounds final. Like you're never coming home."
"I can't promise that I will." His tone was sadder than she'd ever hear someone speak before. "I have to do this, Felicity, but I might not survive."
"I know," she whispered. She did. She knew the cost, knew what he was getting into. She also knew that he had to go or more people would suffer. Innocent people. "I'm not asking you to promise you'll come home. But please don't say goodbye. Because then at least it feels like there is hope."
His eyes softened. He opened his mouth as if to say something, and closed it again, debating. "Felicity, I lo…."
"No, Oliver." She stopped him again, more tears running down her face. "I know. But don't say that either. Please. If you don't…. if you don't come back, it will be easier for me to let you go. Please." Her voice trembled and she just wanted to lose herself in his eyes, pull his lips to hers and kiss him. But she didn't, knowing it would make everything hurt more. The harsh reality that she might never see him again gripped her chest like a vice.
"Okay." His eyes closed briefly and he took a breath. "Okay. But I have to leave, Felicity. What do you want me to say?"
"Say you'll come back. Say you don't have to leave. Say…" a sob caught in her throat. It wasn't fair, she knew. She couldn't really ask him to say any of those things and he wouldn't. She closed her eyes, restraining herself from leaning into him, holding onto him so he wouldn't go.
He took her hand, gently squeezing it. "Don't forget to water the fern for me, okay Felicity?" The pressure left her hand as he withdrew his and she opened her eyes to see the unspoken words swim in his. I love you, goodbye. A heartbeat passed and he was gone.
"I love you," she wanted to call after him. She felt the words on her tongue and in the sob that caught in her throat. But she didn't say a word. She stood in the silence of the foundry, silent sobs shaking her body, despair filling her bones. She knew without a doubt it would be the first thing she said to him when he came home, and knew that despite her requests for him to not say it to her, to not say goodbye, she would love him and wait for him, scared and breaking every moment until she saw him again.
She fell to the ground and cried; terrified that moment would never come.