Now you see them, now you don’t! Maybe you like magic tricks, but when a person disappears and then comes back only to leave and reappear again, it’s frustrating, not entertaining. Even though they may not be a magician, they’re still going to be cagey about their disappearance and reappearance.

Often, they reappear when – to their disappointment – they've discovered that the person they left you for is far from the “perfect picture” that attracted them in the first place. They come back because they've realised that, though you're not perfect, you're a rare breed with flaws they're used to...