How do you define a happy marriage?

During a recent conversation with a 20ish young man I suggested that he needed to begin looking to the future. Staring at me blankly he questioned, “What do you mean. I’m always looking and planning for the future. If you’re talking about marriage – that’s out. I can’t name three happy marriages.”
I was left to ponder the thought of what defines a happy marriage from an outsiders perspective and do I know three happily married couples. I do know more than three couples that I would consider happily married, but does that mean that they are effervescently bubbly, always pawing one another, groping and kissing? No, but their interactions are usually loving and exhibit an overall affection for one another.
That is not to say that at some point in their relationship they have not hit a rough patch. I would say that is what a marriage and any serious committed relationship does. You have good times and bad times and pray the good outweighs the bad.
You may roll over one day and look at the person laying next to you and wonder “How did I get here?” Because on that particular day the person you have vowed your life to has taken you to a place you don’t want to be and you are not very happy with them. This condition may persist for a day, two and maybe even a week or more.
However, at the end of the day if LOVE is what brought you together you will roll up your sleeves and get your hands dirty as you work to rectify the problems.
What are your thoughts? Do you know how to define a happy marriage?