Who knew American soccer fans had such bad tempers? "Loveline" host Psycho Mike has been receiving nasty death threats from U.S. footie fans ... fans who are outraged he's marrying the ex-wife of American soccer star Landon Donovan.
Mike -- who married Landon's ex-wife Bianca Kajlich over the weekend -- tells TMZ ... since announcing his engagement, he's been getting various colorful threats on the Internet.
For example, one person called Mike a "muscle bound roided out greasemonkey that he was gonna stab in the heart."
The ever-tough Mike says he's not scared -- adding he and Landon are good.
As for the rest of the soccer community -- Mike smartly adds, "If I in any way, even accidentally, have done anything to cause deleterious effects to the American soccer team ... I apologize wholeheartedly."
Landon and Bianca -- who stars on "Rules of Engagement" -- were married in 2006. Landon filed for divorce in 2010.