Suppose we plot my preference curve for a man as units of “good boy” traits (thoughtfulness, caring, emotional support) versus “bad boy” traits (adventurousness, sexual attractiveness). My boyfriend, whom I’ve been dating for a year, would come up very high on the former and low on the latter. This situation was fine for me before, but now I’m having a hard time being attracted to him and I wonder if I want to continue the relationship. Has my preference curve simply shifted more in favour of the “bad boy” traits? I know the one year is a sunk cost, but I’m reluctant to give up so easily on such a nice man.
Beatrice

Dear Beatrice,

It is a pleasure to receive a letter that packs so much consumer choice theory into so little space – although I sense a creeping confusion in your question. You speak of a preference curve expressing a trade-off between good boy and bad boy traits. (By the way, I recommend the term “indifference curve”, both because it is technically more precise, and because it makes you sound sexy and unavailable.) Yet you do not specify your budget constraint. You act as if you can have a thoughtful boyfriend or a sexy boyfriend, but not both. I wonder why you think this is true. Perhaps you should hang around with economists more.

Let us take your problem at face value, though, and assume that you cannot simply find a man who has it all. If so, the problem you describe is familiar enough: that of diminishing returns. Only little children want to eat their favourite food for every meal, or listen to the same story again and again. For most of us, variety is the spice of life. So dump your boyfriend and find a rogue. Date him for a year. It is bound to end in tears, and then you can find yourself another ugly, tedious – yet thoughtful – man. They are not in short supply.

Questions to economist@ft.com