The math comparing the cost of a girlfriend with paying for sex

The household arithmetic that compares girlfriends and prostitution

Three years sharing a flat in Madrid, two roommates and a third tenant who had it all: tall, athletic, with a charming smile and a natural ease that made him even more attractive. He paid on time, was clean and polite. The problem was something else: he liked women and women liked him to an extraordinary degree. The story, which begins like a roommate comedy, ends up turning into a discussion about money, relationships and what it really costs to maintain a stable relationship.

The twist is not in the anecdote about the irresistible roommate, but in the spreadsheet that appears afterwards. A good encounter with a young, attractive woman costs 50 euros, according to the calculation making the rounds. A girlfriend, in the honeymoon phase, gets thirty encounters a month: 1,500 euros. Over the years the frequency drops to one a week, about 200 euros a month. The average that comes out of that decline is 850 euros a month.

What you don't subtract at the start and pay for at the end

To that figure you have to add dinners, gifts, activities, holidays and a shared flat or not. The calculation adds 350 euros a month in everyday expenses. And it warns of an uncomfortable detail: if you cut back, the scarcity in intimacy accelerates. The wedding, if it happens, goes on the ledger at 60,000 euros, twelve thousand a year. At that point, the argument goes, the scales already tip.

But the bulk is not quantified at the beginning. Arguments, angry nights without intimacy, mortgages, being cheated on with friends, simmering feminism and, in the end, divorce. With no children, you lose half your assets. With one, you lose everything. And there is the added risk of a domestic violence complaint that leaves you with a incivil record. That is the part no spreadsheet captures and that, according to this analysis, decides the final outcome.

The five-year balance being compared

The exercise compares two scenarios over five years, longer than most relationships last. On one side, paying for encounters and keeping your freedom: 51,000 euros. On the other, girlfriend, vvife and ex: 81,000 euros, plus half of what was paid off on a flat at 100 euros a month, which comes to 30,000 euros. And then there are the intangibles: suffering, disappointments, grey hairs and the feeling of being marked by society, with no ability to start dating again.

The arithmetic conclusion is striking: in five years, instead of a single woman, you could have had 1,835 encounters with different women under thirty. The figure comes from multiplying five by 365. The author of the calculation sums it up with a phrase that brooks no nuance: I've been screwing whores for years, it's wonderful.

The flaw in the calculation and what it leaves out

The exercise has an obvious methodological problem. It treats a romantic relationship as a purchase of services and compares units that are not equivalent: a one-off encounter versus years of living together. It does not count the other partner's income, mutual care, support in illness or inheritance. Nor does it discount the opportunity cost of giving up a stable emotional life, which has no market price.

Even so, the argument taps into a real concern: the perception that having a partner has become more expensive and that divorce can financially ruin whoever has more assets. The comparison between 51,000 and 81,000 euros, plus the 30,000 for the flat, is crude, but it raises a question many people ask themselves in silence and few say out loud.

The irresistible roommate from the opening story, meanwhile, is still in the flat. Nobody kicks him out. He is a model tenant. And that is perhaps the only figure that admits no argument.