Give your life to someone for 25 years (think about what that means and what one gives up for that other person) and then see what you think of that other person if they simply leave you for an upgrade. This is not controversial. It is, however, controversial to consider marriage something either party is free to slip in and out of. I’d like to know which commenters here are married; it’s actually impractical to think of marriage as a non-commitment.
You sound a lot like the catholic church here. It could have been 25 pretty nice years, and in the last 5 both people found that they had grown apart over time and mutually decided they might look for something else (maybe after the kids are out of the house, etc if they have kids). I have no idea if thats the case here. Blanket statements on the morality of human relationships are rather foolish.
