Don't own Bleach. You know how it goes.
Yoruichi had always told him that he wasn't one to think about the little things, and he supposed even now that was true. He may have known about both life AND the science of it, something few in his field could attest to, but that didn't mean there weren't things even he could overlook.
He hadn't noticed the signs, caught the obvious hints. Or maybe he'd simply denied their existence, content to believe what he thought was the truth. He knew that Yoruichi was free, that she didn't let herself fall for anyone, but if it was to be someone, why wouldn't it have been him? All those years they spent together, the time spent training strength against strength; the air of the underground cavern filled with their laughter and playful taunting; the smirking, predatory gaze she wore when they made love.
She'd never been like that before, back when she was just "the princess," back when her topaz eyes were cold and dead, as lifeless as she was despite the firery warmth of her skin that attested to life's presence. But he had been able to reach out to her, to break her gloominess, to bring a brilliant smile to her face and a playful light to her eyes.
He knew that she wasn't the most faithful of partners-- many of those she slept with were people he knew anyway-- but somehow it didn't bother him. He felt completely assured that she'd always come back to him, that she needed him in a way that she needed no one else, not even when she went on to become the head of the Correction Corps. She'd left everything for him, to help him get away that night. Why wouldn't he have believed that she loved him, even if her stoic features never showed it?
He couldn't believe it even though he'd just heard it with his own ears, seen it with his own eyes. The gentle, desperate whisper that had replaced her haughty confidence, the warm moisture in her eyes that looked almost like tears. She was holding her former subordinate, that girl he'd met only once or twice, who he'd believed to be a sister to Yoruichi at best, with such tenderness and passion that he could hardly believe it was really his best friend. She was never gentle, never submissive when it came to lovemaking-- he knew that for a fact, but here she was, letting the smaller girl silence her with equally eager lips, panting and gasping when she could find the breath to utter.
He tried to watch through the crack in the shoji as she told the Captain in her arms that it was her, that it had always been her, that she'd only realized it in the time they'd been apart, in which a hunger had grown between them more powerful than gender, than age or even her feelings for Kisuke. It shouldn't have bothered him but he turned away, trying to block out the sounds of their bliss as Yoruichi screamed out her lover's name, as though taunting him that she had never once done so for anyone else.
He tried to go back to counting his inventory, to checking off the rows of smuggled goods from Soul Society on his clipboard but even then he couldn't help wondering how he hadn't seen it. But he had, years ago before they and Isshin had been forced to leave their home: the less freqent meetings below the Soukyoku; the way she was smiling in spite of her initial dread of taking such a potentially boring position; her frequent remarks of surprise and satisfaction with her new subordinate, marvelling at how quickly she was learning and how dedicated the girl was; telling him with a chuckle about the way she'd snatched some food off her plate at lunch or at the girl's adorable new haircut; the way she seemed to brighten almost imperceptably when her protege was nearby.
It was all there before him but he simply didn't want to believe it then. But he was a scientist after all-- he had to face the truth as some point, no matter how difficult.
The truth was that he wasn't the only one who could make her happy anymore, hadn't been for a century. She'd smile, tease and they'd occasionally sleep together like before but he knew that her heart was somewhere far away, with a tiny girl who no one but Yoruichi could possibly have noticed, have wanted, have loved.
Even later that night, when the Second Division Captain had left the store and Yoruichi and grinned at him and asked how he wanted to spend the rest of the evening he'd wanted to say something. Even after she'd gone to sleep with a satisfied expression only to whisper HER name again he'd wanted to tell her to stop, that he understood and that she didn't have to keep pretending anymore. And yet he couldn't say anything, only brush a hand through her hair and flinch when she groaned and rolled over in her sleep.
The fact was that he was simply too addicted to her to stop, and anything from her was better than nothing.