Imagine that there is an active Catholic layman named "Bob" and that his complicated life has included a divorce or two.

But there is no one person named "Bob." Instead, there are legions of Catholics whose lives resemble this case study described by Father Dwight Longenecker in an online essay responding to "Amoris Laetitia (On Love in the Family)," a 60,000-word apostolic exhortation from Pope Francis.

The fictional Bob is a 1960s survivor and he has "lived that way." His first wedding was on a beach, after he and his lover got high and also got pregnant. Years later Bob married a rich older woman. Years after that he became a Christian in an evangelical flock, where he met Susan -- a lapsed Catholic.

This is where things get complicated.

Bob and Susan "married outside the church, but then Susan rediscovered her Catholic faith and she and Bob started going to Mass," wrote Longenecker. Then Bob converted to Catholicism in a liberal parish "where the priest waved a hand and said he didn't need to worry about 'all that annulment stuff.'

"So Bob became a Catholic and now 20 years later, he and Susan have six kids, a great marriage and are active members in the parish." After a chat with a new priest they discovered that, under church law, they were living in "an irregular relationship. Bob's second wife -- the elderly widow -- was dead, but he reckoned his first wife (the hippie who was married to him for less than a year) was still living somewhere, but Bob has no idea where she might be."

What's a priest supposed to do?

This by no means far-fetched case is one jagged piece of the "jigsaw puzzle" of modern marriage that Pope Francis tried to address in "Amoris Laetitia," said Longenecker, of Our Lady of the Rosary Church in Greenville, S.C.

Longenecker's own story is also quite complex. He was raised as fundamentalist Protestant, graduating from Bob Jones University in Greenville. Then he studied theology at Oxford University and became an Anglican priest. Eventually, he and his wife and children were drawn to Catholicism and, in 2006, he was ordained under the pastoral provision for married former Anglican clergy.

While media debates rage about what "Amoris Laetitia" does or doesn't say, Longenecker said the key is that it "fully affirms the traditional teaching of the church regarding marriage" while making a "valiant attempt to deal with the messiness of real life" at the level of pastors who "deal with the real life situations of ordinary people. We're the ones who have to help them match up their lives with the teachings of the church."

As always, Pope Francis assumes that confession and repentance are part of the path to God's mercy, said Longenecker, reached by telephone. But the pope knows that bishops and pastors work in radically diverse cultures and that there is "no way he could create some kind of step-by-step general rule that would work for everyone, everywhere."

In his introduction, Pope Francis noted: "I would make it clear that not all discussions of doctrinal, moral or pastoral issues need to be settled by interventions of the magisterium. Unity of teaching and practice is certainly necessary in the Church, but this does not preclude various ways of interpreting some aspects of that teaching or drawing certain consequences from it. … Each country or region, moreover, can seek solutions better suited to its culture and sensitive to its traditions and local needs."

So what is a priest supposed to do with the Bobs of this world and other sinners who are suffering?

Truth is, the real stories of real people in real life are often "even more complex and heartbreaking," said Longenecker. At ground level, modern marriages and families are being torn apart by mobility, no-fault divorce laws, economic challenges, cohabitation, promiscuity, pornography and other global changes, said Longenecker.

"I relate these stories to remind readers that for many complicated reasons marriage in our society is a shipwreck," he said. "It's hit the iceberg and gone down long ago. … The pope has made a good effort to help us sort through the wreckage, salvage what we can and build a raft to sail on."