And that's part of the difficulty of monogamy too, really. Not a fight. Nothing big and shaky and earthquaky like a wild, woolly extramarital affair. But the "dark matter" of conjugal reality. That much-of-the-time stuff that binds you together and becomes, inevitably, kind of "so-what." A bit boring. Or, no, just a bit quotidian. The slogging through difficulty which doesn't ever seem to abate. Financial pressure. The other's way of dealing with the things that bug them, which in turn, bugs you. That stuff. The habits that never change. All the things that inspired my Mom to say that the best way to stay married was to live in houses next door to each other. But she got divorced.
I think it's more what Janet was saying. Sometimes the best way to stay married is to stay. Because the moment-that-lasts-a-week passes, the dark matter leads to a bright shiny star, and you see beside you the person you married, except somehow new and improved, because they stayed with you too. That's always the thing that amazes me. As hard as it sometimes is to stay with him, look everyone! he has stayed with me! And we love each other. A lot. More now than before.
And then there's this. As much as marriage may seem a stale affair, it's a growing, shifting beast more comfortable with geologic time then the minutes we count day to day. People do change and grow and experiment within its hold. You don't see it while it's happening, but sometimes you glimpse the results-in-progress, and it's very exciting. The man I married is not the man I'm married to now. But the one I'm with now is better than the one I chose, and he made that metamorphosis in front of my eyes. I feel honored to have witnessed it. I hope he's being gratified by similar changes in me.
NOTE: I have to add this. I don't think that in all cases staying married is the right thing to do. Nor do I think that all marriages are saved by "sticking with them." Nor do I mean to slam people whose marriages failed for serious reasons.