‘Funny – of course it’s funny – but also smart, insightful and sincere about heartbreak' DAVID NICHOLLS, author of ONE DAY 'This is the greatest. You'll cry and laugh. I read it though the night. And I never, ever avoid sleep' CLAUDIA WINKLEMAN ‘I award it 13/10 on my QWJ scale (stands for Queasy With Jealousy that I didn't write it)’ MARIAN KEYES --- Every relationship has one beginning. This one has two endings. Andy loves Jen. Jen loved Andy. And he can't work out why she stopped. Now he…