What makes my marriage good, what makes me happy, is the daily work we put into it and the long-term history we have together.

I'd go one step further. I hope I wouldn't trade up, even if the marriage wasn't good at the time. I hope I wouldn't trade up, even if I wasn't completely happy. Besides abuse, injury, or unavailing and unrepentant toxicity, there are few obstacles that would make me abandon ship for a better model.

The reason being: relationships aren't always good. Period. Some days you're bitter, exhausted, and want to be selfish. Some days you can't appreciate, love, respect, or even think positively about the other person, for whatever reason. Happiness is fleeting and inconstant, and won't always be found. Life is complicated, and people are messy. Sometimes you have to face big difficulties, and your frustrations won't stay neatly compartmentalized--they'll seep and spill into every area of your life. Sometimes, difficulties can last for days, weeks, months ....years (?). We'd all like to think we'll do the right things at all times, no matter how hard life gets. But, we won't. Sometimes you manage brilliant acts of love, care, affection, and consideration in the darkest hours. But, let's be honest, we're all just doing the best we can at every stage.

Maybe I'm too idealistic, but I'd like to think that people can make a pact, and hold to it in spite of all those difficulties. I mean, no one really has to. They don't have to stick around. It's not like a video game, where you lose points for leaving. You don't get a slap on the wrist. No demerits. Even if there isn't a better model down the street, everyone is free to carve out whatever path they want to walk. But, to me, that's why it matters to stay. I like the thought of making the best of it, come hell or high water--when you don't have to. Just because you said you would.

I'm in my late 20s. I actually don't know what I would do, of course. I've never been in that situation. But I always had the deepest respect for the people who put up a good fight.