Derek Medina's post said his wife, Jennifer Alfonso, had been abusing him, The Miami Herald reported. Medina had not yet been charged late Thursday.
Facebook removed the pages of husband and wife.
Officers who went to the house found Alfonso's body and Medina's 10-year-old daughter. The girl was not harmed.
In his post, Medina described physical abuse: "My wife was punching me and I'm not going to stand anymore with the abuse so I did what I did. Hope u understand me."
"I'm going to prison or death sentence for killing my wife," he added. "Love you guys. Miss you guys. Take care. Facebook people you'll see me in the news."
The Herald said court records show Medina, 34, and Alfonso, 26, married for the first time in April 2012, divorced and married again.
Medina has written books he published himself. The titles include "How I Saved Someone's Life and Marriage and Family Problems Thru Communication."