Cowboy's Triplet Trouble by Carla Cassidy

She had one reckless one–night stand and now Grace Sinclair has to face the fact that Justin Johnson, her triplets' father, is an irresponsible cad. But his cowboy brother Jake smoldering hot and single welcomes Grace and her infant daughters to their family's Oklahoma ranch. It's a quiet place until someone tries to kill the single mom!

After years of cleaning up Justin's messes, ,Jake wants no responsibility for him or anyone. Even as he protects Grace and feels a powerful sexual desire for her, he assures her they have no future. But when the killer makes another brazen attempt on Grace, Jake finds himself rethinking his life alone and those three adorable babies.