This weekend, we celebrate our great American pastime: messy celebrity divorces.

There’s the Christie Brinkley/Peter Cook fireworks on Long Island and the Madonna/Guy Ritchie/A-Rod Roman candle in New York.

So how do you avoid a relationship where you end up saying, “The man who I was living with, I just didn’t know who he was” — as Brinkley did in court when talking about her husband’s $3,000-a-month Internet porn and swinger site habit? (Not to mention the 18-year-old mistress/assistant.)

Father Pat Connor, a 79-year-old Catholic priest born in Australia and based in Bordentown, N.J., has spent his celibate life — including nine years as a missionary in India — mulling connubial bliss. His decades of marriage counseling led him to distill some “mostly common sense” advice about how to dodge mates who would maul your happiness.

“Hollywood says you can be deeply in love with someone and then your marriage will work,” the twinkly eyed, white-haired priest says. “But you can be deeply in love with someone to whom you cannot be successfully married.”

For 40 years, he has been giving a lecture — “Whom Not to Marry” — to high school seniors, mostly girls because they’re more interested.

“It’s important to do it before they fall seriously in love, because then it will be too late,” he explains. “Infatuation trumps judgment.”

I asked him to summarize his talk:

“Never marry a man who has no friends,” he starts. “This usually means that he will be incapable of the intimacy that marriage demands. I am always amazed at the number of men I have counseled who have no friends. Since, as the Hebrew Scriptures say, ‘Iron shapes iron and friend shapes friend,’ what are his friends like? What do your friends and family members think of him? Sometimes, your friends can’t render an impartial judgment because they are envious that you are beating them in the race to the altar. Envy beclouds judgment.

“Does he use money responsibly? Is he stingy? Most marriages that founder do so because of money — she’s thrifty, he’s on his 10th credit card.

“Steer clear of someone whose life you can run, who never makes demands counter to yours. It’s good to have a doormat in the home, but not if it’s your husband.

“Is he overly attached to his mother and her mythical apron strings? When he wants to make a decision, say, about where you should go on your honeymoon, he doesn’t consult you, he consults his mother. (I’ve known cases where the mother accompanies the couple on their honeymoon!)

“Does he have a sense of humor? That covers a multitude of sins. My mother was once asked how she managed to live harmoniously with three men — my father, brother and me. Her answer, delivered with awesome arrogance, was: ‘You simply operate on the assumption that no man matures after the age of 11.’ My father fell about laughing.

“A therapist friend insists that ‘more marriages are killed by silence than by violence.’ The strong, silent type can be charming but ultimately destructive. That world-class misogynist, Paul of Tarsus, got it right when he said, ‘In all your dealings with one another, speak the truth to one another in love that you may grow up.’

“Don’t marry a problem character thinking you will change him. He’s a heavy drinker, or some other kind of addict, but if he marries a good woman, he’ll settle down. People are the same after marriage as before, only more so.

“Take a good, unsentimental look at his family — you’ll learn a lot about him and his attitude towards women. Kay made a monstrous mistake marrying Michael Corleone! Is there a history of divorce in the family? An atmosphere of racism, sexism or prejudice in his home? Are his goals and deepest beliefs worthy and similar to yours? I remember counseling a pious Catholic woman that it might not be prudent to marry a pious Muslim, whose attitude about women was very different. Love trumped prudence; the annulment process was instigated by her six months later.

“Imagine a religious fundamentalist married to an agnostic. One would have to pray that the fundamentalist doesn’t open the Bible and hit the page in which Abraham is willing to obey God and slit his son’s throat.

“Finally: Does he possess those character traits that add up to a good human being — the willingness to forgive, praise, be courteous? Or is he inclined to be a fibber, to fits of rage, to be a control freak, to be envious of you, to be secretive?

“After I regale a group with this talk, the despairing cry goes up: ‘But you’ve eliminated everyone!’ Life is unfair.”