Note: I did not watch Richard Belzer as Detective John Munch in his original series, Homicide: Life on the Streets so I did not get any information to include on this entry. Instead, I'm focusing on John's time on Law & Order: SVU.
John Munch had been married four times: his first wife was named Gwen and fourth wife named Billie Lou.
Gwen appeared once on Homicide: Life on the Streets when she turned to John after her mother died for help with the funeral arrangements.
Billie Lou was John's girlfriend and bartender at his bar as a recurring character on Homicide: Life on the Streets. They got married in the series' final episode.
John also had a brother named Bernard who worked in the funeral parlor. He appeared twice on Homicide: Life on the Streets and was only mentioned once on Law & Order: SVU when John recommended his brother's services when Olivia's mother died.
John had a wedding anniversary on April 4th (with which wife? It's unknown)
Each of John's wives were beautiful, spoiled and none of them matched his intellectually. John distrusts women- he gave up on relationships- but still believes in true love. The pain of not finding it is unbearable.
John's wife had some pretty foul habits. By the second season, his soon-to-be-ex had been calling him with requests for money and updates on the status of their uncoupling. They're not together anymore but they still fought- only he's not there for the tantrums.
John's father killed himself when he was 13. John thought it was his fault: the night before his father blew his brains out, he punished John for being a wise-ass. John told him that he hated his guts- those were the last words John ever said to him. It haunts him to this day. Amy Soloway was the only person John ever told in depth because they're the same. He felt guilty as his father was suffering, he couldn't help him. John didn't want Amy to die (after she refused a kidney transplant or else she would go to prison for assisting suicide).
John has a cousin who's a "G-man" for the FBI
10 days later, Andrew was cleaned up and back to normal and came over to the squad to take John out to lunch and to pay his thankful respects to Dani. He felt that he had to be at court for Brent Allen Banks' trial as he slaughtered the little girl who tried to help him when he was sick. Andrew ended up causing a scene in the courtroom and had to be escorted out. Later, while Elliot and Dani were keeping an eye on Brent, they found Andrew in the area to try to help them. Andrew was having a manic episode. Dani tried to distract Andrew to keep an eye on Brent's home but he followed Elliot and Dani to the subway while following Brent and his female companion. Andrew pushed Brent in front of a moving subway, killing him. Andrew was admitted to Rockland Psychiatric Center. He didn't want to get help- he felt responsible and needed to pay for his crime.
The Mehcad Carter case hit John pretty hard enough to turn in his papers to retire from SVU. John was thrown a farewell roast party, sharing memories and laughs with his past colleagues, two ex wives, and his brother David*. John transferred to work at the D.A's office as a special investigator.
*As mentioned on the very top of the post, in Homicide: Life on the Streets, John's brother was named Bernard but on SVU he was called David. Hmm?
Billie Lou's Episode