"And his dark secret love/ Does thy life destroy"- What does the expression 'dark secret love' mean? What does the poet mean by this?

In Blake's poem "The Sick Rose", the expression 'dark secret love' refers to the illegitimate love of the worm. Because of this element of mystery involved in the love affair, it becomes 'dark' suggesting mysterious. So the expression 'dark secret love' means love that corrupts the rose insidiously in the darkness of night.

        Here the poet simply expressed that the dark secret love of the worm destroys the life of the rose. But the inherent meaning suggests that beauty and purity is corrupted by the evil forces, represented by the worm. Now the rose has lost her innocence. Because of this deceitful social love, she is sick with same.