Mistress?

"I never said I was complaining," Rachael smiled. "It's good that you are getting used to me, at least I don't have to worry about you running away with another woman." 

"Actually, that doesn't sound like a really bad idea." When he pretended to think, she pouted her lips and slapped his chest. 

"Don't even think about it," she threatened. "First I'll kill you and then the mistress before fleeing the country." 

"Oh my—" He chuckled. "You know I have heard many threats in my life but this is by far the scariest one." 

"It's good that you are scared." She patted his chest. "At least this way you'll always be careful." 

"Why would I even need a mistress when I already have such a beautiful and fiesty wife?" He raised his brows. "And if I ever end up getting one, feel free to admit me to some mental asylum because I am a freak."