First off, you know who is in the wrong in this confrontation. It's definitely not you. He's smart and knows how to twist words around. He's older. However, you have it within you to beat him. He's used to your same old tactics you used in the past so now, its important to come back with a different approach. Maybe come back at a later date. It's also important to make sure you feel safe before confronting. If you have a bad feeling about it at the time, its good to let it go and come back at a time when you feel more comfortable.
One thing that helped me was practicing in front of a mirror or just talking to myself, planning out what I was going to say and preparing for any come back he could have. For ex: "quit being a wuss, It's not that big of a deal, you wanted to do it, you let me do it, I was young, etc." These are all cop outs my perp used and I was ready for them. I let my brother know how I felt about him and the damage he had caused.
Someone may have mentioned this author to you already, but if you get a chance, check out "The Courage To Heal" by Laura Davis. It's a big thick yellow book you can get at any bookstore. There is a section on confrontations in there that you might want to check if you get the time. It did me a lot of good. As a matter of fact, if you haven't read it, I would recommend going through the whole book. I can't even describe the good it did for me.
Good luck and be safe. You'll beat this. We are all pullin for ya!
Jason