The problem I think is that people expect it to make their lives better by default. Its one of those things where you get out what you put in. A relationship should be more like an ongoing project (a rewarding one) rather than an accomplishment. A lot of people get married because its a goal...or even a rite of passage. A social norm. Something that your just supposed to do.
Then, after the honeymoon period its, "Ok. Now what?".
Now its time to put on the gloves, do some stretches, and be married.
Keep laying bricks I guess. Dunno. I'm still a novice I suppose. Can't figure out how my grandparents, in their late 80s, who've been married since the damned Truman Administration, haven't completely lost it. Sometimes they even hold hands. Its wild.