The reason is simple: Clare didn't get Tess in the first place. Not to mention Yuan Liang. What Clare loves is just a desire to get a pure body, and Tess has only existed as Clare's vision of a pure girl before. And after learning that Tess has lost the so-called "pure life", Clare lost his desire for Tess. These "stains" are excluded from Clare's visionary framework, but when these "stains" burst into fantasy space, the vision loses its seductive power and transforms into a disgusting object. It's not that Clare doesn't really cool Tess, but clare wants to make himself not forgive Tess, to cover up that he didn't really love Tess before, to cover up his vulgarity, and to prevent him from facing up to and hating himself. What clale can't forgive is the fact that he didn't love Tess before, what clale can't forgive is himself. On the contrary, Tess really loves clare with all his heart.
In the end, Clare's return was just to prove his own greatness, nothing more.
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