Gorgeous SOFIA VERGARA will flip when she learns her on-again, off-again BF, trust-fund baby NICK LOEB, is secretly refusing to end the relationship with his wife, say sources.

Although the Modern Family hottie from Colombia knows Nick is still married, he promised her he’s getting a divorce.

 Nick’s estranged wife Anna has been pushing for him to sign the papers and make it official, but he’s been dragging his feet, The ENQUIRER learned.

"Sofia will be livid when she finds out Nick is refusing to take the final few steps to sever his marital ties," a close source revealed.

But as the ENQUIRER previously reported Nick’s close call with death in a horrific car crash changed their relationship forever.

Yet now, the billionaire playboy secretly refuses to pull the plug on his marriage.

Learn WHY only in the new ENQUIRER – on sale NOW!