Part of every Christian romance is the presence of the Lord. He is a third character, embued into the soul of our hero and/or heroine, and standing guard over their thoughts, actions and deeds.
Writing His presence can be a daunting task. You want to give the reader a sense of God, but not get preachy about it. You want the reader to know that God is always present, but that he never interferes with free will. You want to quote Scripture, but not make it sound stilted or out of context.
When writing, we tend to want the story to be just so, and will often create a scenario where God is there, but out of sight. Instead, let God fill the scene naturally, as a character, rather than the ghostly presence of the hero/heroine’s conscience. Rather than writing about her/his faith and belief, write how they see God in everyday things or events.
Showing God’s majesty, in song, Scripture or prayer, will create the foil that allows characters to come before Him and accept His will in their lives. The characters should not just turn to God when there is a crisis. They should be interacting with Him on a daily basis, thanking, praising and worshiping the Creator of all things.
When an unbeliever crosses the path of the believing hero or heroine, they should get the sense of God that makes them wonder and become curious enough to explore their options, eventually discovering God themselves.
Shoe-horning God in as an afterthought is like inviting a clown to a funeral. The negative connotation sticks out like a sore thumb. Draw on your own relationship with God and make His presence fill your pages with the glory that is within yourselves. Bring the real, living God to life in your words, and use His Word to reinforce His character.