Urgent Vows (Intrigue, 571)

the long version

He asked her to be his wife, a mother to the children -- and before the night was through...possibly the widow — Quin McClure had no right to show up on her doorstep after five years, looking sexy and desperate, with two tiny orphaned children in tow, asking for an impossible favor. And yet, one look in Quinn's eyes, and her heart answered yes before she knew it. Quinn knew that if something happened to him before he could find his brother's killer, at least he could see that Hope and the children were safe. But being with Hope again reminded him of the wasted years they'd spent apart. Now with a killer on their heels, Quinn had to stay alive for the children - and for Hope, who loved him as only a true wife could.