Emily,
I can sympathize, having gone through the same thing. Once.
There are red lines in life that cannot be crossed. You not only have to realize that, but now you will have to work to get the trust back in your marriage. I'm afraid that putting "Emily in the attic" will probably not go very far in that regard. If she knows you did that, you're already fighting a losing battle, and if she doesn't know now, but finds out later, the battle will be lost.
Normally, for some of our situations, therapy or counseling could be suggested, but I would suggest that if you're considering that, that you hold off for a better time. You could get some solo counseling now, but I would suggest you not try to get her to go. Not now, and if she ever does, you may want her to use a different counselor. From not only my own experience, she may well view it as you and the counselor trying to gang up on her and force her to be the one who needs to change, when she feels perfectly justified in having the opinion of the situation that she has. And, like it or not, she is 100% correct. Showing her you care enough to get counseling on your own can only help.
You're not going to like my advice, but I have to tell you straight up, that she is the aggrieved party here, and to think otherwise is only being selfish of you. I think by now, you can see that this is not a light-hearted, happy-go-lucky, all good for you affair. It's serious shit, and you need to fully appreciate both the situation you have created and just how strong her feelings are about it. This one's on you, and you will have to make a great effort to fix it. Or leave it. That depends a lot on just where your head is at. Step back, figure out what is REALLY most important to you, and go from there.
As I said, I really, really do feel what you're going through, and I can only tell you that it's all up to you now. I wish you the best of luck, and hope that you figure this all out.
While it may seem I'm being hard-hearted, I'm not trying to be. I will also point out, to those of us here, and those of us considering being here, that this, and related subjects, have been discussed before, and having taken the time to read all of that may have prevented this situation from occurring. and may prevent it for others in the future. Far too many of us "don't have the time to be bothered to see what all is here." Say what you will, I spent 2 weeks of evenings reading every single post before I joined. This "growing breasts", whether or nor you view it as such, is a commitment, and should never be treated lightly.
Maybe it's in the male mind-set that we think we know more about wives and women than we do, but that could only get us in trouble when we disregard the feelings of the others in our lives. Please, please, use this site for educational experience as well as growing breasts. It's so much more than that.