From Paula McLain’s Love and Ruin:
“We can’t lose sight of what really matters,” I told him, easing against his neck and shoulder and kissing him there.
“Hmm?” he asked sleepily. “We won’t.”
“I mean it, Rabbit. Even when other things come in loud, we have to keep choosing each other. That’s marriage. You can’t only say the words once and think they’ll stick. You have to say them over and over, and then live them out with all you’ve got.”
floridianne 
This is so, so true. Some might think that is especially true in the early years of marriage, but I think more so in the later years . . . when you know your mate quite well, with all the quirks and idiosyncrasies and the little splinters that easily get under your fingernail and can quickly cause division.