I understand your point. Some couples seem destined to remain devoted and it can feel like a personal tragedy when they break up, like something has torn in the fabric of the universe. It's like when a favourite sportsman dies who you remember from your youth. They seem eternally young and athletic, but then old age or illness takes them and you realise they weren't young anymore and it's a reminder of your own mortality. But you're perhaps too young to experience that feeling yet.