It may sound strange to say, but all of you are lucky who get to do this part on your own and on your own terms.
Perv/STBXH took this away from me. Do you know what he did? The second night he snuck out in the middle of the night while DD and I slept, he apparently called every single one of my relatives and told them what he was doing.
So I woke up with my entire life changed and no clue, while my relatives had that knowledge. Do you suppose any told me? No.
Further, they came from out of state to have "holidays" with DD and I and they knew all the while about the A he was having, while I and she did not. Stayed over night at my house, ate my food, played with my cat, visited with me politely and all you do with company...
And all the while they had this knowledge again about myself and DD. When I think of this I am infuriated at all of them and only two did not know.
My father is one. He knew Perv had intention of leaving but not about OW. My siblings, mother, aunt and uncle knew of OW but chose to say nothing.
I don't mean to turn this into a vent or all about me, but another point of view is that it's one small piece of the whole thing that you have control over.
Oh, one more thing...Perv also took it upon himself to go to my place of employment and spoke to them and I have not been asked to return since. I was a sub. teacher's aid at DDs school and it took almost four years to get in as far as I did.
It is a horribly crappy thing to have to tell people, but yet another point of view that's happened here, is if you as BS don't tell people, your WS will at some point or they will learn of it and it may not be what you want them to hear...when Perv told his family, he minimilized and made it about all these problems I supposedly had, but don't. He tried to make it like it was his "only choice and he could not work with me anymore", when I begged to work with him.
So as hard as it is, I would always vote for telling anyone any of you care about or would want a relationship with in future.