I'm crying just reading this, my adrenaline is rushing and I want to kill someone!!!
I can only imagine what you must be feeling right now, and your clarity and strength are shining despite how gut wrenching this must be. My suggestion to you is to NEVER EVER let your daughter feel like she can not talk about it, should move on (I don't care how old she is). Don't project your feelings on to her, and always meet her where SHE is. Get some support for yourself- this abuse victimizes the whole family and I am sorry to say that you will never be the same family you were before that moment... I am so sad for your daughter, and for this boy who has a very difficult life ahead of him.
As an adult survivor one of the hardest things is having my abuser (my father) remain in my family, remain in my life because the poeple around me felt it was 'over', and 'done with'. I had to shake people and beg them to see that by not talking about what happened to them, to me, that we are BREEDING the ground for it to continue! Don't ever let her feel that she is a burden, ykwim? If you feel she could benefit from it, get her into play-therapy. Use art at home to help her talk about her feelings. Make it fun, open and safe for her.
I don't have the words to express the intensity of the feelings I have reading what your sweet, innocent daughter experienced, and my celebration that she has the ability to speak to you about what she went through (I think it's so critical for kids to know the right words for body parts!).
You are not alone, your daughter isn't alone. Find out the number for the crisis line in your area because there will be times when it will be handy for you (trust me). Sometimes just talking to an invisible, uninvolved person helps, sometimes you just need to rage and not dump it all on someone you love- these lines are there for that.
Nurture yourself, nurture your family. Many, many
for you and your sweet baby girl, and your Dh who will doubtlessly want to come home ASAP after he finds out. Please keep us updated.