Brighton had wanted to keep Henderson until January but that would have meant that Villa would be unable to recall him should he be needed.
"I'm pleased to be staying, but it's frustrating because I won't be getting as many games as I would have if I had stayed until Christmas," he told the official Brighton website.
"The club [Villa] aren't in the position to do that, so I've had to jump at the chance of two months.
"It's just frustrating but at least I've got the two months so I can play another ten games or so."