Double Wedding Ring by Lizbie Brown
The vicar performing the marriage service is surprised to see the bride walking up the aisle on her own - and is even more surprised when she throws off her veil to show that she's not the bride, but the groom's jilted, pregnant mistress. After publicly humiliating both Johnny, the groom, and herself, Kat Gregg resolves to look forward and think of the baby to come. But that night she is shot dead. Elizabeth and Max are called in by Johnny's mother to prove him innocent of her murder, and find themselves investigating a rat's nest of illicit relationships, domestic abuse and blackmail before they finally find out what really happened the night Kat was killed...