After having read the rest of your thread, my above response still applies, but with the significant addition of this:
She is literally the only man in the world that she trusts, and trusts completely. Her past and your subsequent actions have made it this way. And, although I felt badly for her before, I feel even more so now.
My advice, honestly, is end this. For her sake just as much as yours. You will never, never, never gain the trust she has for this guy, ever. You were already at a disadvantage from the get-go with this, but having been unfaithful to her (twice) has completely taken that out of the equation. You had a chance at one point, and now it's gone for good.
People who have gone through this kind of trauma absolutely require somebody they can trust (as much as they are able to). You have shown that you are not it. For 15 or so years, he HAS.
It can be completely amicable. You can still co-parent. Everybody will be happier.
This ^^^^ natsanjose, about the best that you can do.
As for having to drag details of the relationship out of you, all that I can say is that one does not go to the doctor, tell the doctor about some symptoms but not all, and then expect to get a decent diagnosis.
One can't come here, give part of the story, and then expect to get good advice.
Everyone knows that rape is traumatic. A rape victim who later becomes a victim of infidelity will generally never recover from that betrayal, because they tend to look sexual intimacy differently than others.
Once you cheated on her, her feelings about sex with you most likely changed from something that was loving and intimate, and yet stressful to a degree because of a feeling of vulnerability, to exploitation for your personal gratification.
Cheaters have no business making vows to anyone, but even more so, with victims of sexual assault.
The reason that you left out key details to begin with, was because you knew what the responses would be. I don't know why you'd want advice based on a false premise, as that type of advice is worthless.
Yes, it is better that you moved on. You destroyed an already fragile person with your infidelity. Sorry.