Ken Budd fell for his high school sweetheart all over again when they reconnected after college.

Both were 25 when they married. He just assumed they’d have kids one day, something he had always wanted, but it wasn’t until his father died 14 years later that he even broached the subject with his wife. The result?

“I wanted to have a child and she ultimately didn’t,” Budd said. “She said she just felt like she didn’t have maternal feelings.”

Far less has landed couples in divorce court, but the Burke, Va., couple — he an editor and she a nurse — made it through. Budd, now 46, said he gave up the parenting dream and channeled his fatherly feelings into volunteer work on behalf of poor kids all over the world, trips his wife came along on a couple of times.

“You both wind up feeling guilty,” said Budd, who wrote a book, “The Voluntourist,” about his travels and the reasons for them. “She feels guilty because she knows I wanted this thing but she didn’t feel like she could do it, and I feel guilty because I’ve put her in this position where she feels guilty, so we both had to work through some things.”

Whether it’s having children at all or how many to have, divorce attorneys and therapists said the issue rears regularly, but it’s unrealistic to think couples can close the negotiation before heading to the altar.

Talking about it, at the very least, is a good idea before the rings are on.

“You may resent your partner for denying you something that is so important to you. On the flip side, if you pressure a spouse into having a child they don’t want, it can be detrimental not only to the marriage but to the child as well,” said Lori Freson, a therapist in Encino.

It’s easy, she said, to pretend before the nuptials that a kid divide doesn’t exist.

“Denial and avoidance can be very powerful, especially in a love relationship,” Freson said. “Love makes us do crazy things. Most people in love don’t want to acknowledge the reasons why it might not work.”

Sometimes minds can change.

David Knoller is 65. He retired a few months ago as a medical research administrator at a hospital near his Fair Lawn, N.J., home. His wife, Rochelle, worked as a librarian for more than 20 years.

They have a 28-year-old son who, Rochelle noted wryly, “doesn’t know how lucky he is to be alive.”

The Knollers met in the summer of 1976, in line to renew their driver’s licenses in Manhattan. They married the following January. Like the Budds, Rochelle was 25. Just about all of her friends were single at the time, and of one thing she was certain: She didn’t want kids.

“I had had a pretty unhappy childhood. I certainly didn’t enjoy the child part of it, but my parents didn’t seem to be having a good time, either,” she said. “I had made up my mind not to have a child, and that was it.”

David, who is five years older, was aware of her feelings. He knew he wanted to be a dad, but love won. They were best friends who enjoyed hanging out together. And they were young. They were having fun.

“I figured time was on my side,” he said. “I figured that it was a discussion that could be deferred until we really got to know each other.”

It worked, about six years later, when Rochelle decided without urging to get pregnant at a time she was having trouble getting her career in recreation therapy off the ground. She trained later in library science.

“I occasionally used to wonder if I had found librarianship earlier, would I have made this same decision, and will never know, obviously,” she said.

Jacqueline Newman, managing partner of a Manhattan family law firm specializing in wealthy clients, said Rochelle’s turnaround isn’t unique.

A variety of factors is usually at play once somebody comes knocking on Newman’s door. When having kids is one, a change of heart by one or the other often surfaces, she said.

“Your priorities shift, lifestyles shift,” Newman said, noting the case of a husband she once represented. “Both didn’t want kids, then he decided he did once they were married. She felt completely tricked by it. Both earned lots of money, so things like hiring a nanny or quitting her job weren’t a problem. She just felt like, ‘We made a deal. You’re changing the terms of that deal.’ ”

Count Newman among experts who believe premarital discussion of when, whether and how many kids to have can only help, even though partners grow older, careers evolve and minds may change.

While her clients are high earners, money comes into play for many couples

According to a U.S. Department of Agriculture report issued in June, a middle-income family with a child born in 2011 can expect to spend about $234,900 ($295,560 if projected inflation costs are factored in) for food, shelter and other necessities to raise a child over the next 17 years.

That’s a 3.5 percent increase from 2010. Expenses for transportation, child care, education and food saw the largest percentage increases, with smaller hikes in housing, clothing, health care and miscellaneous expenses.

Being clear on parenting desires is crucial heading into marriage, said Ramani Durvasula, a psychologist in Los Angeles.

“This can actually be a backbreaking challenge for a relationship” because of the high potential for “unfixable regret,” she said.

“That trip to Paris you didn’t take 10 years ago can be addressed even when you’re in your 70s, but decisions about kids have numerous ramifications in terms of lifestyle, finances, stress, identity.”

Often, Durvasula said, couples get lost in the easy question of “Do you want kids?” They need to go deeper, “into the dealbreakers like how many? Spacing? Will one parent stop working? Where will we live? And if one person assumes having kids means four, and the other one — that could really lead to tremendous strain and even a sense of betrayal if agreement can’t be reached.”

A form of “bait and switch” may develop, she said, “which can result in telling a new partner what he or she wants to hear to cement the relationship and then reneging once the deal is sealed. Not a good idea.”

Leigh Cummings, a family law attorney in Atlanta, sees the kids issue among her clients about 15 percent of the time. When she asks why it wasn’t discussed during courting, the responses are usually “it didn’t come up,”said Cummings. “Or we were just in love, or she thought she would change his mind. It’s a huge, festering problem.”