For once, it's not Tim Tebow who's having trouble scoring - it's his girlfriend.

Confidenti@l is told the QB's model squeeze Olivia Culpo has dumped him after a two-month relationship - because he won't have sex with her.

The former Miss USA, who was first reported to be seeing Tebow in early October, has told friends that she can't deal with the famously abstinent star's nookie-less lifestyle.

"He was really into her," a source close to the model told us, "he was sending her love letters and cute notes and professing his love for her."

Alas, Culpo took a knee.

"She had to break up with him because she just couldn't handle it," said our insider, "He still hits her up, but she just can't deal with the sex thing. He's pretty adamant about it, I guess."