Rules of the Secret Society of Young Widows:
Rule 1: Be a widow.
Rule 2: Have an impeccable reputation.
Rule 3: Don't fall in love again.

AN HEIR TO SPARE by Rebecca Connolly:

Widowhood has changed much for Ann, Lady Lyndham, but an unconventional heir to the estate was not something she had anticipated. Yet, Ned Richards, the new Lord Lyndham has a world of surprises in store for her, and not anticipating them will become quite the adventure.

THE WIDOW OF LAVENDER COTTAGE by Jen Geigle Johnson:

As a widow, Lillian Hunter never plans to never marry again, so the rules of the Secret Society of Young Widows suit her just fine. Until Oliver Wentworth arrives. Oliver is not pleased to discover that a widow lives in a tiny run down cottage bordering his new property. And confound her, she challenges his attempts to help manage her affairs.

A PROMISE FORGOTTEN by Heather B. Moore:
Charlotte Ashford never thought she'd find herself widowed with a young child to care for. She certainly never thought she'd return to Somerset and see him again. But Lord Wilshore hasn't forgotten their promise made long ago. Charlotte would love nothing more than his forgiveness, but too much heartache might make that impossible.