Before he allegedly gunned down Jennifer Hudson’s mother, brother and nephew, William Balfour was cheating on her sister, according to a witness who testified in his triple murder trial!!

Diana Grant told the Chicago courtroom that she met the defendant in 2007 through friends, she found out Balfour was married to Julia Hudson a few months later but says she was already in love with him and they continued to date.

The revelation of the extra-marital affair caused the most animated reaction yet from the Oscar winner and her sister, who sat whispering heatedly while they heard how Grant met Balfour – whom she nicknamed “Flex” and “Baby” – at hotels for illicit hookups, bought him clothes, and even put up with him dating other women.

Balfour faces three counts of first-degree murder, aggravated kidnapping and home invasion in the 2008 deaths of Jennifer and Julia Hudson’s mother Darnell Hudson Donerson, brother Jason Hudson, and Julia’s son Julian King.

Thomas Kinkade passed away nearly three weeks ago leaving behind a wife… and a mistress whom he planned to marry!!!

According to reports, Thomas and his wife, Nanette, had been separated for nearly a year before his death and he had been living with his mistress, Amy Pinto-Walsh.

A source reveals, “They were planning on getting married as soon as the divorce was final. Amy was already part of his circle of friends and that really enraged Nanette. She was furious and humiliated that he not only cheated on her, but moved on so quickly and publicly with her.”

Thomas was a recovering alcoholic who was convicted in 2010 of a DUI — much to the dismay of his large Christian following — and had fallen off the wagon, drinking heavily in the 24 hours before he died.

A guy was in battlefield serving his country for 9 12 months, and he comes back to a pregnant girl?! Hmm…