This sentence expressed a kind of emotion, namely loyalty and respect for one's partner. The speaker expressed love and concern for his or her partner but also said that if his or her partner fell in love with someone else, he or she would not feel resentment or blame. This is because the speaker believes that his or her partner's love and loyalty are irreplaceable. He or she is willing to respect his or her partner's choice, even if it means that his or her partner will leave him or her. This sentence conveyed the values of respecting and cherishing a partner's loyalty and feelings, even if it meant leaving him/her. It also implies love and concern for your partner even if he or she makes some choices that make you unhappy or uncomfortable. These feelings and values often appear in romance novels to express the protagonist's love and loyalty to his or her partner, even if he or she has to leave his or her partner to pursue his or her own happiness.