Nicholas "Nick" Amaro, most likely born in the late 1970s to early 1980s, is a detective who transferred to the Special Victims Unit from narcotics and warrants in 2011. He is charismatic and charming, often using his charm to get difficult witnesses who won't cooperate to talk.
Family
Amaro is married with one child, a five-year-old daughter named Zara (Allison Fernandez). His wife Maria (Laura Benanti) was in Iraq and returned on Valentine's Day. (SVU "Personal Fouls") Nick is a Catholic, fluent in Spanish, and also apparently has good connections with the community. Amaro's father beat his mother when he was younger, and later fled to Miami, Florida; he attributes his firm belief in divorce to this. He and his wife have recently split up, Maria having moved to L.A. to take a job taking Zara with her.
While undercover on a narcotics bust, Nick had a relationship with the sister of a major drug dealer. "Undercover Blue." 9 years later, the relationship is brought back to light, when a court case involving rape accusations against Brian Cassidy throws Nick under the bus. The woman, Cynthia Mancheno, claims that she had a son by Nick during that relationship, named Gilberto. When a paternity test confirms this, Nick attempts to spend more time with his son, who believes that he is Nick's nephew. In "Born Psychopath", Cynthia gives Nick permission to reveal his identity to Gilberto.
Personal life
He has no sympathy for people who rape the mentally ill or children. In "True Believers" he says his rank is Detective Second Grade. He worked in vertical patrol in housing projects for 6 years "Educated Guess" He seems to be protective of Amanda Rollins and is suspicious of his wife dating other men while in the Army and afterwards, assaulting a friend of hers he believed she was having an affair with after she lied to him about where she was. She denies having an affair and finally reveals to him that she is seeing a psychiatrist and didn't want him to know.
He was forced to kill a man in "Hunting Ground" and has trouble it being his first kill in the line of duty.
Later on it was discovered that his wife Maria Grazie took a job in L.A. claiming that they needed a break from each other.
It has also been hinted that Nick and Amanda have been in a relationship for quite some time since he emerges from her bathroom during "Reasonable Doubt" and comfortably sits on her couch. Aside from his protectiveness for Amanda, his attraction to her has been previously hinted on in episodes like Gambler's Fallacy. He's usually the one to realize when something is wrong with her. The nature of their relationship and whether Olivia and Fin know has not been revealed yet.