According to "The National Enquirer", TIM MCGRAW has a "secret son", 23-year-old Tyler Zarbo. However, it's not as scandalous as it sounds, but . . . still. He is NOT Tim's biological child, he's actually the son of Tim's former fiancée, Kristine Donahue.

The "secret" part is that Tim has been supporting Tyler, although it's not clear how . . .  but he hasn't told ANYONE about it, including his wife FAITH HILL. Tim LEFT Kristine FOR Faith back in the mid '90s. Faith and Tim were married in 1996.

For some reason, the "Enquirer" is also painting Faith as insanely jealous. 

A source said quote, "Every time Tim glances at another woman, Faith jumps all over him. She's never forgotten that Tim broke up with another woman to be with her, and she's worried that he could do it again . . . to her." 

Apparently, back when they got married, Tim promised Faith that he would never lie to her, and he doesn't.  Instead, he just withholds the truth.  

The source said, quote, "[Tim] doesn't tell her everything. He keeps some secrets to keep the peace."

At least the "Enquirer" did talk to Tyler . . . and I feel sorry for the guy. I mean, if he's telling the truth, and I have no reason to think he's not. He said, quote, "Tim McGraw was like a father to me when I was growing up. 

"He saw me as the son he never had, and we've stayed in contact. I wish he could have remained as my substitute dad, but it just wasn't meant to be."

As you'd expect, as soon as this story got out, Tim's people issued a statement. Here it is:

Quote, "The 'National Enquirer' story is full of inaccuracies and misrepresentations about Tim and Faith. We aren't going to comment on false statements that appear to have been sensationalized for the purpose of selling tabloid magazines."

The rep isn't denying Tim's relationship with Tyler. It sounds to me like the "inaccuracies" and "misrepresentation" are the parts that show Faith in a bad light.