Like Lena, about whom he could rarely bear to think, she made him ashamed; and with shame came anger—the old familiar leper’s rage on which so much of his endurance depended. By hell! he fumed. They had no right. They had no right! But then the uselessness of his passion rebounded against him, and he was forced to recite to himself as if he were reading the catechism of his illness, Futility is the defining characteristic of life. Pain is the proof of existence. In the extremity of his moral solitude, he had no other answers.
Lena made him ashamed?!?!... (Oh, yeah, it's all her fault how he is feeling bad about himself...)
His own actions should fill him with shame. He is the shameful one. Lena offered him nothing but kindness and he raped her.
As for futility ... If, Covenant wants to define himself as powerless and meaningless that's on him ... futility is not a necessary feature of life.