What to expect when telling my sisters

Hi,

I wondered if anyone had advice for how to tell my sisters that our father abused me as a child?

I am 37 and I decided a long time ago to never tell them as it would be too upsetting. However now we all have children I feel they need to know so that they'll protect the children. He is part of our lives and I'm worried that makes it look less...believable? I am so worried about telling them. I love my sisters so much, I can't bear to think of them not believing me, feeling angry/upset I didn't tell them before, it's such a mess. They won't understand why I've kept this lie and pretend happy families. When really I have this huge secret that will shatter their lives.

I really hope someone has a positive experience to share too?

I've been seeing a therapist to have to strength to tell them, I feel pressured to do this soon, I am in a bad place right now.

Thank you