It's those slight differences in life. She has no reason not to love you. you have been a supportive husband, you help raise the kids, take care of the household chores. You are always there for her no matter what. No you have never cheated on her or done anything to make her mad at you or hate you. She loves you and always will. You are a cuckold, you encouraged her to be with other men. Now she has fallen in love with one. She is in love with him. She cares for him like she does you. There is an emotional connection. When she met him, something stirred within her that she hadn't felt in years. The sex is amazing, great sex, the same she has with more well endowed dominant men cuckolding you. With him though his laughter is infectious, his passion for adventure ignited a forgotten spark in her.
Her heart flutters with excitement every-time he texts her, when he smiles at her a warm blush spreads across her cheeks. The feeling of arousal for him is new and thrilling, making her feel alive. When she gets wet and fantasizes about getting fucked it is him she thinks about. It is him she thinks about when thinking about travel and romantic weekends away. When she is away from him, it is him she is thinking about. She checks her messages hoping to see a text from him. It is him she wants to spend more time with emotionally and sexually. She loves you, like she loves her kids and her best friends but she is in love with him. The funny thing is, you love her so much, and cuckolding so much, it is the peak of arousal you have felt on this journey.