The first time she realized they were coupling on the regular, it took her three days to calm down. She had a first-class snit fit, thinking she'd been tricked into a relationship. Words she'd almost regret later were thrown at Xigbar, accusing him of all manner of things he'd done to trick her. When she finally calmed, she hid in her rooms and wouldn't come out for a full two days. The blonde contented herself for the time being with the thought that they were part-time lovers, and that was all. It wasn't true, and a part of her knew it. She didn't apologize, of course; it wasn't in her nature.
The second time, there was a flower on her bed. Nothing too fancy, just a little dahlia- appropriately black. She almost threw it away, but didn't. She could never quite decide why she hadn't. Things would have been so different if she had. That night, she made the decision- quite on her own- to try and recruit him. Larxene consoled herself that he was powerful and useful. He listened intently, and there was a nagging itch on the back of her neck that told her all was not well. Ah well. If he betrayed them, they'd kill him, too. It was simple enough.
The third time was much different than the first two. She kneeled in front of the room she was caged in, beating against the door uselessly, her lightning wearing her out more than the marble. The blonde screamed and shrieked and ranted her anger, venomously threatening him and everything he could have come to care about. She didn't understand why she'd been separated from the other traitors, but she would damn well find out. Without her rank, and no longer a part of the Organization, she had no reason not to try and kill him- did she? If she didn't, why did it hurt? And it did, hurt, in a place she'd thought long dead. What she didn't know was heartbreak only served to make her angrier, railing against any weak emotion that could cost her all she'd worked for.
The fourth time, Xigbar tried to tell her. He nearly admitted what he felt, had felt for a long time, but the look of utter hate on her face stopped him. Larxene had spent the last three months telling him to leave her alone, and he was close to giving up. She opened her mouth to give him another flippant 'Go to hell', but something on his face stopped her. Wait, she thought. Remember. This is a man you laid with because he was powerful. He's still powerful, and even more so now. She resolved herself to listen. He said nothing.
The last time, she knew. It took her days to say so, but finally she sat down outside of his room and waited for him to come out. When he did, she glowered at him. "I love you, too. Moron. You're not even worth it, I don't know why I try." With that, she walked away, pretending to sulk.