I posted on the last thread that I'd had a similar experience to that of OP. I was 15 when I was raped by two men - no drugs involved. I was also a victim of child abuse.
I have absolutely refused to allow myself to be defined by this history. It drove my professional ambitions as I was determined I wasn't going to be brought low by those losers. I'm now an academic. They're still losers. OP, you've engaged in therapy, raised a family, and made a fulfiling life for yourself. You're not reducible to your trauma, but given your husband's actions and those of the abhorrent 'B', this must be how you've been left feeling. It's truly despicable.
My husband finds my history uncomfortable even to talk about. In the past this has hurt, especially before my cPTSD was diagnosed and I was living with some of this entirely in my present and unable fully to move on from it. (This is what flashbacks do, in the form I had these). He has, however, supported me through two years of therapy and has tried to listen, although he doesn't necessarily know what to say. The thought that he could define himself in relation to my trauma, share it with friends, tell his mother, his boss, and play the knight in shining armour role to something I have tried valiantly for years to leave behind, would horrify me. Imagine after all these years suddenly discovering your husband was not the man you thought it was - and THIS is who he really is?
My heart breaks for you, OP, but do know that your decision as to what to do about your marriage is yours alone. You'll be in shock. EMDR does help. It's a long, painful process but the best hope for the treatment of trauma. However, this could very well have retraumatised you, and with EMDR you do need to seek further therapy if this happens. You're not under pressure to make any immediate decisions.
Look after yourself first and I hope you're able to seek support from others. You deserve better than this.
💐