Continue with the divorce and push for at least primary custody because there's no telling what private info the douchebag now has or what he's capable of and your daughter needs to be kept safe from that.
Try to separate what she did from how you deal with it, remember you still have to be an example to your daughter and our children don't learn from what we teach them, they learn from what they see! Pornkai has a zero-tolerance policy against illegal pornography.
It shouldn't be on him to think about it feel bad honestly.