People don't realize just how meaningful family and marriage can be. Think about it like this.
In your job? You are expendable. You are nothing but a cog in the machine. I work in a pretty high-demand field, I make pretty good cash, but at the end of the day, I know that if I quit, I'll be replaced within the week. There's a line of about several thousand people who can quite easily take my place. There's no meaning in that. No fulfilment.
In a marriage, however? As a father or a mother? You cannot be replaced. If you get married, become a parent, and then die? Your family is going to miss you, forever, and even if your spouse remarries, and the new parent is just as loving and caring as you were, your spouse and your kids are never going to be able to fully replace you. They will spend the rest of their lives with a massive you-shaped hole in their lives. Assuming you're a loving parent and not abusive, of course, but you get the point.