The "if" in Deronda's case carried reasons of both kinds; yet he had never throughout his relations with Gwendolen been free from the nervous consciousness that there was something to guard against not only on her account but on his own--some precipitancy in the manifestations of impulsive feeling--some ruinous inroad of what is but momentary on the permanent chosen treasure of the heart--some spoiling of her trust, which wrought upon him now as if it had been the retreating cry of a creature snatched and carried out of his reach by swift horsemen or swifter waves, while his own strength was only a stronger sense of weakness. 
Deronda had never throughout his relations with Gwendolen been free from the nervous consciousness that there was something to guard against, not only on her account but on his own - that any impulsive action on his part would ruin her trust in him, which worked upon him now like the retreating cry of a creature snatched and carried out of his reach. 