You ARE doing the right thing. I went through this disclosure experience last November and I can share a few points that proved to be very important for me.
1. Tell people in a neutral place, avoiding, if you can, any special place in the house. The reason is that afterwards, that place will be the spot "where Jerry told us".
2. You will have to give them what my T called a "plausible framework". You should be willing to tell them who abused you, of course, but also, in general terms, how long things went on and what happened. On "what happened" you don't have to be graphic. In my case I just said "Everything you can imagine and some things you probably can't imagine."
3. If you feel that your parents were not to blame, your mother will need to be reassured of this. My own parents felt totally gutted that this happened and they had no idea. I made a special effort to assure them that back then (early sixties) the abuse of boys wasn't on anyone's radar.
4. This will be an enormously draining and exhausting experience for you. I hope you will let your wife in on everything that happens and rely on her support. That would be a great help.
Please also call on us here. Post whatever and whenever you can and we will support you in any way possible.
I hope this all goes well, and yes, I agree it needs to be done, not just for your sake, but also to make sure the new generation in your family is not being hurt. If there is a shitstorm of anger and denial, so be it. Just remember that what you are doing is right.
Nobody living can ever stop me
As I go walking my freedom highway.
Nobody living can make me turn back:
This land was made for you and me. (Woody Guthrie)