I liked M. L. Tyndall's pirate series. Sadly her latest work does not involve pirates, but rather the world's worst spy.
Okay, seriously, to read and enjoy this book, give up any expectation for realism. The characters, action, etc. do not fit the early 1800s. And while it is a Christian romance, it's probably one of the "edgier" ones.
Here's the plot: Dominique is being forced to spy for France in order to save her brother's life. She unwillingly does so, agreeing to become a governess for an English admiral's son. Surprise, surprise: the governess and admiral fall in love/lust. There's emotional turmoil because the (young) admiral has been widowed; he doesn't belive in God anymore; and dang, that governess is hottttt. Dominique, on the other hand, is the world's worst spy; it is simply amazing that the admiral was too blind to see her actions.
Anyway, there's a happy ending and all that, including the admiral turning back to God. That was probably my biggest issue of the book. I firmly, firmly believe that you need to marry someone on your spiritual level--and someone who believes the same as you. Otherwise, you're heading for a load of trouble. Dominique is a Christian and the admiral has turned his back on God. He starts to pray at the end and everyone seems to think that everything is all right again. There wasn't true repentance and salvation; it was a "ok, let's make everyone okay with God so they can get married" ending.
I think the best example of that sort of ending is the Cheney Duvall series--Shiloh actually leaves her and goes away for awhile to fully develop a true relationship with God, without any distractions. That spoke true sincerity to me and a putting of God first above everything else. I didn't see that in this book.