I have got to find..
this novel that William Luse is quoting. Check out this bit of dialogue involving a couple coming in to plan their wedding (man is a fallen-away Episcopalian, woman a less-than-exemplary Catholic), and the priest who has had to deal with this kind of nonsense one too many times....

"This could go on a long time, Father. I've given my promise. What more do you want?"

He slammed his fist against the desk in a tight, swift gesture that caused Liz to flinch. "I want more than your promise! I want to know there's something holier in your life than your own damn opinion. I'm sick and tired of my Catholic children coming in here with their pagan fianceés, all of them, of course, like you, pledging undying love, and then a year or five years later," he snapped his fingers, "it's over." He ceased, allowing the heat beneath his collar to subside, his voice to calm. "Of course," he admitted, "I see quite a few pagan Catholics as well, and they have no cloak for their sin. But it comes to the same thing: many of my flock now live their days in great sorrow because a promise wasn't enough." He leaned forward to fix me with the blue eyes. "What I want to know is that after God joins you beneath the roof of his house, the walls of your marriage will not come tumbling down with the next change in the weather. With any change in the weather. That's what I want to know."