He knew what he felt was wrong.

Those ugly.. brewing emotions that churned and blossomed the more time he spent with you. Byakuya couldn't find himself to care as such for those feelings--he'd never expected to fall in love again either.

He knows you wouldn't approve of him this way, but Byakuya knew he wouldn't be able to fight the sensations that flourished. The urge to keep you safe, that same twisted love.

So he welcomes it. There was no need to cut the bud in the nip, after all.