That depends. What is the goal of the "final talk"? Is it for you or to save what's left of your marriage? I'll answer either way after I say one other thing.
You asked about the stats on here. I doubt it could even be unearthed because so many people leave without saying what happened. From the experience of being here quite a while, I'd say the odds are pretty long. It's not based on fact, but I'd say the odds for women with walk-away husbands is better than that for men with WAWs. The odds are actually better, I think, for LBSes with cheating spouses, since when the affair dies, they start thinking about reconciliation. Best guess all told for success? 10% But when I look at the people who I once posted to, more than half, maybe even 2/3 of those people posted for a couple months, even up to six months, then disappeared. I'd have to assume that those people ended up divorced.
Anyway, about your original question. If this talk is solely about getting things off your chest, then you can say whatever it is you want. You can say you are hurt, disappointed, sad, angry, that you think things could be different, or whatever is on your mind because when you get to a certain point in all this, it isn't really possible to do much more harm. That would be just so you can feel better. Don't expect her to care what you have to say though.
If it's a last ditch effort to win her back then I think your talking points are much more limited. You can either let your actions speak for you and not have this "final talk", knowing it will probably not do you any good and may in fact push her even further away to the point she doesn't want to talk to you at all, or you could keep it simple. "This is not what I want, but I understand your reasons behind wanting a divorce. I only want to see you happy, so if this is what it takes for you to acheive that, then I have to let you go." You could indicate that you feel things could be different, but I'd be prepared for disbelief on her part. Seeing is believing. Were I you (and yes, I've been through this part), I'd probably just keep it simple without promises that things would be better if you tried again. Don't cry. Don't fuss. Don't beg.
In the end, it's not the years in your life that count. It's the life in your years. Abraham Lincoln
It is hard to fail, but it is worse never to have tried to succeed. Theodore Roosevelt
