"In the criminal justice system, sexually based offenses are considered especially heinous."

That same introduction has played over every episode of Law & Order: SVU for the past 13 seasons, but the message will hit especially close to home this week for Det. Nick Amaro.

"Just like our voiceover says at the beginning of every episode, these are truly heinous crimes. I think there is only so much that certain people can take," Danny Pino tells TVGuide.com. "It starts to erode his confidence within his own marriage."

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On Wednesday's episode (10/9c on NBC), Amaro will take his recent suspicions about his wife (see: last week's episode when he followed her to a mystery man's doorstep) to the next level. "He's been following her and suspecting that she's been less than honest," he says. "In this episode, it comes to a boil and there's no way to really stop it."

The tension in Amaro's marriage is not only a result of his recent career move from narcotics to sex crimes, but also of his wife's job that puts her in the war zone thousands of miles away from her husband and daughter. "While she was overseas, I think he started feeling an emotional distance between them," Pino says. "That, underscored by the nature of crimes that he is investigating and the inherent psychological deceit that he witnesses every day, affects him to a point where he needs to take action within his own household."

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Pino says he and showrunner Warren Leight were anxious to explore the aftermath of traveling overseas and into a combat zone since they first began crafting Amaro's backstory at the beginning of the season. "It represents something that is happening now," he says. "When soldiers who are enlisted start coming back and seeing how they reassimilate into society and what they bring with them. And how the people who are here — family members and friends — have changed as well."

However, Pino admits it was unclear what direction Amaro's marriage to Maria would take. "That was largely decided upon by the chemistry between myself and Laura Benanti," Pino says. "We play Skype scenes together where she is in one room and I'm in the other and we're essentially looking at a screen. Even within those scenes, there seems to be a familiarity."

Amaro's trouble at home comes just as he seems to be hitting a groove at work. Two weeks ago, Det. Benson (Mariska Hargitay) memorably told Amaro he was a good partner — a big step for both her character and the series in the wake of Christopher Meloni's surprise exit. "It is probably the only relationship Amaro has right now in his life that he feels confident in," Pino says. "That speaks volumes to not only how his relationship with Olivia has developed, but it also to how his relationship with his wife has devolved."

Law & Order: SVU airs Wednesdays at 10/9c on NBC.