Dear Economist,

I have just joined a dating website in the hope of finding true love. Friends of mine have started dating someone they met online, only for a “better offer” to arise on the website. If this happens, what should I do?

Duncan, London

Dear Duncan,

The possibility of upgrading to a better relationship is not new, but internet dating allows more offers to be considered and so the tried-and-tested rules of thumb may no longer be appropriate.

It might seem natural simply to consider how many offers you must sample until you are likely to meet “Ms Right”. That would be naive. You must instead balance the benefits of choice against the effect your flightiness may have on your targets.

These decisions are much like those faced by a company choosing the optimal number of suppliers. Dealing with more suppliers allows the company to choose the cheapest and best. But having too many makes suppliers insecure and unwilling to invest in the relationship.

Your ideal choice depends on what you want. Fun and frolics are ideally obtained by keeping options open, perhaps even switching to the spot market. But if you want your partner to have your babies, support you while you write your novel or share the cost of buying a home, you will need to reassure her that you do not have other competitors waiting in the wings.

In some industries it is common to sign contracts with two suppliers - enough competition to keep each on its toes, but enough commitment to inspire big investment in the relationship. In your case that would be a wife and a long-term mistress. Perhaps the tried-and-tested rules of thumb work after all.

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