How do you develop a romantic relationship in a mystery series? Most importantly, keep things slow and subtle. You don’t want to resolve the romance by the end of book one. Build it step-by-step, advancing or retreating each stage per book.
Give your characters internal and external conflicts to keep them apart. The external conflict is your mystery. The internal conflict is the reason why they hesitate to get involved in a relationship. Maybe your heroine was hurt by a former lover and is afraid of getting burned again. Or she has a fierce need for independence because she has to prove herself worthy of respect. Why? What happened in her past to produce this need?
Keep asking questions to deepen the motivation. Maybe your hero doesn’t want a family because his own parents went through a bitter divorce; and secretly he feels he isn’t worthy of being loved. Or maybe he suppresses his emotions and doesn’t know how to give affection. Whatever the opposite sex character does appears to deepen or challenge this inner torment.
Your characters are immediately attracted to each other through physical chemistry. This pulls them together while the inner conflicts tear them apart. Yet for the relationship to succeed, it must advance. The benefits begin to outweigh the risks. As they become emotionally closer, your characters progress through the stages of intimacy.
Stages of Intimacy:
1. Physical awareness: Your characters notice each other with heightened sensitivity. For example, he is aware of her physical attributes; identifies her personal scent; feels a response in her presence. This may include a racing heartbeat, coiling warmth, tingling skin, etc.
2. Intrusion of thoughts: Your character begins thinking of this other person often; he/she invades your character’s mind.
3. Touching: First, it may be an arm around the shoulder, lifting a chin, touching an elbow. They come closer until the desire to kiss is almost palpable. Rising sexual tension is the key to capturing your reader’s interest.
4. Kissing
5. Touching in more intimate places
6. Coupling: Focus on the emotional reactions of your character. Avoid clinical terms or use them sparingly if at all. This is lovemaking, not just sex. For it to be romantic, think "slow seduction", not "slam bam, thank you ma’am".
Throw a wrench into the relationship when all seems to be going well. His former wife appears on the scene; the heroine does something thoughtless and alienates him; he feels pressured and backs off. Finally, they both change and compromise to resolve their differences.
Here is how this work in my Bad Hair Day mystery series (spoiler alert):
PERMED TO DEATH: Hairstylist Marla Shore meets Detective Dalton Vail. [girl meets boy]. While instantly attracted to each other, they share a mutual distrust. Marla is the prime suspect in her client’s murder [external conflict]. Vail is suspicious of her, and rightfully so. Marla hides a secret that gives her a motive. Meanwhile, Marla is suspicious of Vail’s interest because she thinks it’s a pretense. He wants to get to know her in order to learn what she’s hiding.
Besides the external conflict, Marla and Dalton have several internal conflicts at the start of the series. Marla doesn’t want children because of a past tragedy, and Vail has a preteen daughter. Marla values her independence after divorcing a domineering attorney, and Vail tries to direct her behavior. Vail, having lost his wife to cancer, is afraid of losing Marla. He wants to protect her, but she keeps placing herself in jeopardy. She interprets his protective behavior as telling her what to do. Thus they have several issues to overcome before intimacy. At the story’s end, he asks her for a date and she decides to accept [relationship moves forward].
HAIR RAISER: Marla meets Vail’s daughter [forward]. Marla dates an accountant who earns her family’s approval but he may be a murder suspect [backward]. Marla and Vail share their First Kiss [forward].
MURDER BY MANICURE: Marla takes Vail’s daughter, Brianna, to dance class [forward]. Marla pretends to be her friend Arnie’s fiancé so he can rid himself of an amorous old flame. They bring Vail into the scheme to date this woman. Marla gets jealous of Vail when he pays the lady more attention than her [backward]. Marla earns his daughter’s regard [forward].
BODY WAVE: Marla’s ex-spouse, Stan, enters the picture when his third wife is a murder victim. Marla and Vail work together to solve the case [forward]. Stan stirs up feelings Marla would rather forget. Vail is jealous. Marla accuses him of wanting to pin the murder on Stan [backward].
HIGHLIGHTS TO HEAVEN: Marla and Vail argue over his restrictive rules for Brianna, and Marla feels she has no place in their life if he won’t listen to her advice [backward].
DIED BLONDE: Vail proposes [forward].
DEAD ROOTS: Vail meets Marla’s extended family; he presents her with engagement ring [forward].
PERISH BY PEDICURE: Marla meets parents of Vail’s dead wife. Vail takes their side [backward].
KILLER KNOTS: Marla meets Vail’s parents on a cruise. She and Dalton set a wedding date [forward].
And watch for SHEAR MURDER coming in January 2012 to see what happens next. Most of my fan mail is about Marla and Dalton. That should tell you something about what readers care about. Keep the conflict alive to keep your readers interested. Even if your couple gets married, nothing is perfect, is it?