Not his vanity, but his keen sympathy made him susceptible to the danger that another's heart might feel larger demands on him than he would be able to fulfill; and it was no longer a matter of argument with him, but of penetrating consciousness, that Gwendolen's soul clung to his with a passionate need. 
He felt the danger that her heart might make larger demands on him than he could fulfil; and he knew that Gwendolen's soul clung to his with a passionate need. 