Jacob Elisha Downer, 29 of Marietta, was airlifted to Grady for treatment Friday at approximately 10:20 p.m. but doesn't remember a thing that happened, according to Gordy Wright, spokesman for the Georgia State Highway Patrol.

Downer was found in the roadway on Meadowview Rd. in Lithia Springs.  There was no visible evidence on his clothing, no witnesses, no one who heard anything, no roadway evidence and no vehicle evidence at the scene, Wright said in an email.

The father of three sustained broken bones, has a severed thigh muscle, and may need bone skin grafts from road rash, according to a report by myfoxatlanta.com. The man's fiancé, Lindsay Davenport, said that it will be at least two months before he'll be able to stand on that leg, according to doctors.

She said it was a hit-and-run driver and is pleading for the driver to come forward.

"The neighbor heard him screaming for help and so the neighbor came and saw that he was on the ground," said Downer's fiancé to myfoxatlanta.com. "Both of his hips had been broken, they have a bolt going through one hip into the other," said Davenport. 

"I understand someone having the sheer shock and panic, but to take off from the scene is something I can't fathom," she said.

Lindsay told myfoxatlanta.com that Jacob's spirits are good, but he has a long recovery ahead.  The couple have been dating for nearly seven years and plan to tie the knot on Nov. 17.

"I'll push him down the aisle if I have to," said Davenport.