"I don't know how people manage to have two kids," the 32-year-old computer engineer said.
He and his partner insurance worker Nadine Rodriguez, 32, together earn around €2,300 ($3,000) per month.
The couple pay over €500 monthly to leave Pablo part-time in the daycare, from 7:30 am until 4:30 pm.
The couple can't afford the full-time fees (until 8:00 pm) at the private centre and, with few public daycares available, Rodriguez has scaled back her hours at work to be able to look after her son — leading to €300 less in monthly earnings.
The couple took out a 40-year mortgage in 2006 to buy a one-bedroom apartment which is hard to sell in favour a larger home, due to Spain's depressed real estate market.
They would like to have another child but can't imagine that happening anytime soon.
If they did, "it would probably be more economical to not work," said Rodriguez.
The couple's struggle to raise a family is typical in Spain, where the work day often extends well beyond 7:00 pm, affordable daycare is hard to find and public aid to young families is scarce.
As a result Spain has since the 1980s had one of Europe's lowest fertility rates. It stood at 1.32 children per woman last year while the average age at which a woman had her first child was at 31.6.
Spain's birthrate rose modestly during the 2000s as the economy boomed and immigrants poured into the country, but the trend went into reverse after a property bubble burst in 2008, sending the jobless rate soaring to a record 27 percent.
With fewer and fewer future workers and taxpayers being born, Spain faces what could be a fiscal reckoning to provide for its ageing population.
The low birthrate "puts the survival of the welfare state" at risk, said Salome Androher, the general director for family and childhood services at Spain's health ministry.
After Spain returned to democracy following the death of dictator General Francisco Franco in 1975, women poured into the workforce, she said.
"But this massive arrival was not accompanied by the necessary changes in society," said Androher.
Spain needs to adopt more measures to make it easier for women to balance their home and work lives, said Julio Perez, a population specialist at Spain's National Research Council.
"They are charged both with their traditional roles as well as their new roles. The process which will take us to greater equality is not yet completed," he said.
Many couples in Spain rely on their parents to look after their children.
Nearly half of all Spanish grandparents said they looked after their grandchildren on a daily basis, in a 2011 study.
The Spanish government in 2010 eliminated a €2,500 bonus awarded to the parents of each newborn child since 2007 as part of austerity measures aimed at reining in the runaway public deficit.
Rodriguez gets €100 a month from the government as part of a programme to aid working mothers of toddlers.
She hopes to qualify in the new school year for a monthly allowance of another €100 paid by the Madrid regional government to help cover her daycare bill.
State aid though is not enough to boost fertility rates, according to Perez.
"During an economic downturn, the state can do what it wants, but if someone wants to raise a child in good conditions, it is normal that they will put off their plans until another time," he said.
Among developed nations, the countries which have higher fertility rates "are not those that focus on birthrates but those that focus on creating equality between men and women".
Spain's conservative government is working on a plan to make it easier for families to balance their work lives with the need to look after children, which will be tabled at the beginning of 2014.