Agatha Raisin and the murderous marriage - M. C Beaton

The morning of Agatha's marriage to James Lacey dawns bright and clear. But her luck runs out in the church when Jimmy, the husband she had believed long dead, turns up large as life and twice as ugly. Agatha has a go at strangling him. James breaks off the engagement. So when Jimmy is found murdered next day, Agatha and James are both the prime suspects. And they'll have to work together in order to clear their names . . .

"Beaton's dry sense of humour and her unflattering but affectionate portrait of gruff, often adolescent-acting Agatha makes this a bloom worth picking."
Publishers Weekly