Jackson admitted that while the breakup hurts, what is more painful for him are the "horrible blogs" that have speculated on his subsequent change in appearance.
The 38-year-old actor cleared the air, saying, "I do have a mustache, but it's for the new Ira Sachs movie [Love is Strange] with Alfred Molina and Marissa Tomei and John Lithgow, so that's what that's for. I do have a new tattoo, and it's personal. I'm happy to tell [the story behind it] now because it's out there, but you know, it's for my dad."
The new ink displays song lyrics from an Elvis song that his father sang to him when he was growing up.
"It was a beautiful, beautiful moment between us and, you know, it's very special," said Jackson. "And for that to be kind of reduced to gossip fodder is obnoxious."
Jackson went on to confirm reports of him joining Alcoholics Anonymous, saying that he began his recovery last summer.
"Some members of my family didn't even know I was in Alcoholics Anonymous, so that was pretty f***ed up to actually have people [find out that way]," Jackson fumed.
As a supporting cast member on the FOX hit Glee, Jackson also touched on his fallen co-star Cory Monteith, calling him "kind."
"That was the first thing that struck me about him, was his kindness," said Jackson. "You could tell he was a leader among the cast and I found out later it was because he was 30. He had that baby face and played a 16-year-old but he was definitely a grown man."
The Frank DeCaro Show airs weekdays at 11:00 a.m. ET on SiriusXM OutQ channel 109.