From the GP article that transcribed the interview...
But Biden may have known something about Obama, something out of his personal life that Obama had to hide. He makes Biden his vice president. Biden always had this saying about Obama that he told him, "I want to be the last guy in the room after everybody leaves when there's a big deal to be done."
I want to be the last guy in the room with you. That's probably when Biden told him, "Okay, you're going to do this with me because I know this."
...
We used to get the Air Force One passenger manifest. Obama would fly back and forth to Chicago. When he flew back and forth to Chicago, very rarely, maybe only less than five times, he would go there all the time because that's where his political office was for re-election.
Michelle and the kids never went with him. So he would go back to their home, their house, where they were born and grew up without his family. Why would he do that? Michelle Obama was a Chicago girl.
So the man actually said that he's only guessing that Biden was blackmailing Obama based on the fact that Biden was his mentor and was given "big assignments," and his theory that Obama was having a gay affair was based on Obama flying to Chicago without Michelle and the kids.