The thunderbolt, that intense feeling of love that can strike you at first sight, or in the early days of a relationship, isn't grounded in anything but gut feeling and lust, yet it is absolutely essential for a good relationship. It's the little voice in your brain that says, “Wow, he's really hot when he's angry”, thus protecting you from his nonsensical argument.

The thunderbolt is also a liar; it's not on your side. If you're anything like me, you'll be on a sleeper-train to Edinburgh with the man peels mangoes with his teeth and quotes from Withnail and I before it dawns on you that basic struck-dumb attraction will not carry you through a two-day holiday, let alone a relationship.

And, the thunderbolt frequently misfires. I was desperate to believe that I was compatible with Voldemort (nicknamed by my friends for his root-of-all-evil antics), in spite of mounting evidence that he didn't have a sense of humour.

In reality, the thunderbolt is probably our reaction to sex pheromones; namely, that Voldemort smelled of compatible genes. Not on a conscious level (it was like sleeping beside a wad of musty towels) but whatever chemicals were wafting from his sweat glands had my brain screaming, “Procreate!”

Funke Baffour, a couples therapist, says: “It's important to have intense feelings of love for your partner, but there must be balance. The intensity naturally ebbs and flows and cannot be sustained permanently, nor should it. If it is a constant feeling, an obsession, then it's likely that you're not being realistic about the person you're with. Likewise, if you never have this feeling, then you should be wary. If the other things that keep you with that person fade, you may wake up one day wondering why on earth you're with them.”

Verdict If you're not feeling it at all, or you're feeling it too much, it's a deal-breaker.

LAURA DEELEY

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