Inspiration Romance Book?

I am searching for a Christian romance book I read a while back, and I can't remember the title. It is kind of an Old Western. A woman is abducted by outlaws, and one of the outlaws escapes with her. They go and hide in a cave. It turns out he is actually a Pinkerton agent (I think) and he had infiltrated the gang to bring them down. I think his name is Dave or David. In the end of course they end up together. I do remember that I loved it. I want to find it so bad! I have searched everywhere. So, I am hoping that someone out there has read it and remembers the title. I would be forever thankful. Please help me!