The 25-year-old left the ABC competition last week after telling Pavelka that she had to choose between him and her job. She requested to return in Monday night's episode, but Pavelka told her that it was not a good idea.
Speaking to Extra's Terri Seymour, he said: "Ali was my frontrunner. I basically begged her not to go.
"I did want her to come [back], she left me, Terri. There were three women who didn't. Who would I have sent home?"
Fedotowsky added: "Do I regret what I did? Yes. When I see Jake, I think I made the wrong choice."
The Bachelor continues next Monday on ABC.
> Click here for our full recap of this week's episode of The Bachelor