What does Thomas mean by letting Teresa die in The Unbearable Lightness of Life?

Theresa has been pursuing the perfect unity of spirit and flesh all her life. But love with the body can't belong to the soul completely. The happiness of the body is the opposite of the purity of the soul. What Thomas means by letting Teresa die is: If you want me to be yours. Only death can end the happiness of the body. . . In fact, this book is a philosophy book, not a novel. His center is flattery. Sabina stands for betrayal. Teresa is the responsibility. This book is particularly difficult to understand. You'd better watch some literary appreciation when you read it. Pick me. I said so much. I am exhausted.