Once a Cheater I guess is always a Cheater in my case

I have been having an affair for over 2 and a half years. I actually left my wife for her and lived with her for over a year. I broke it off with her and got back with my wife. We never divorced. But the affair with the girlfriend has never stopped. I tried to stop it many times. She always uses threats and sex to keep the affair going. I have read all the stories above and I'm in the same pickle as many of you. My girlfriend is so in love with me that she will do or say anything to keep this going. This is not an ego stroke for me. It's more of a hassle than anything. I actually love both of them. Weird, but I have equal feelings. That may sound impossible, but it is very true. I went back with the wife because I missed her and the kids(all grown) and everyone had disowned me when I left her. That has been repaired. I don't want to mess that up again. But my girlfriend wants me to move back in with her and I just can't. Me and my son own a business together and there is just too much at stake. I started the business for him(probably out of guilt) and I just opened up the 2nd location that I run. I met the GF when I was going bankrupt because of the tanking economy, so she isn't in it for the money. I work 12 hours a day, 7 days a week running this business and so does my son. It leaves little time for my girlfriend, but she accepts that. We meet for short periods of time. It seems that no matter what, she will always want me and claims that if that is the only way she can have me, then it's okay. She does have fits of rage and threatens telling my wife and kids, but she never has, even when I didn't talk to her for a month. My situation is different though. I don't want to end it with either. I thought I did, but everything just kind of happened and it ended up this way. I tell them both that I love them. The sex is over the top with both of them. They know each other, but they don't know that I am sleeping with other. But they don't talk to each other. My wife doesn't know that the affair never ended. My Girlfriend thinks that I don't sleep with the wife. In other words, I have given up trying to be with just one of them. I am a great liar and I can talk my way out of anything. I'm not proud of myself at all. I know that I am a piece of garbage. I'm 45 and have the libido of a 20 year old, but I have hypertestosterone levels naturally. When I married my wife 23 years ago, it was because she is very pretty and had an equal libido. That never changed. We still have sex almost daily. The girlfriend and I meet at least 3 times a week. When I was living with the girlfriend, me and the wife were still having sex. They switched positions for a year. The GF is a sex maniac also. I guess I am content with this situation. Maybe I am just warning women out there to not strip a man from his family, because there is a good chance we will go back. Especially if your family disowns you. I love my family, wife and Girlfriend. GF and wife hate each other's guts. I would like some suggestions on what to do, because I know this will some day come to a head and they will both find out about each other. Weird, but I know that even if they did, my wife wouldn't divorce me or ask me to leave. My GF would get pissed off for a month, but then start seeing me again. I know I am scum of the earth in many women's eyes right now. But maybe this can give you some insight into the male brain. I am not a narcissist. I really do love my wife and my
Girlfriend and care about them both deeply. I can't help myself.
sorry