you don't have to cut yourself open again. No one gets to decide what you risk in your R but you. If it's not healthy for you to do that, then just don't until you feel it's safe to do that.
The reason Heather got into this mess in the first place is that neither she nor her H felt safe enough to make themselves vulnerable. Each kept holding onto a power position waiting for the other to go first. Heather has been extremely brave in backing off this power trip. She is still trying to find the correct recipe to make her self vulnerable in a way her H can hear, but I read your comments as telling her to move back to a defensive position. I think this will only resurrect the power plays.
I'd say.. if exposing your thoughts and feelings is going to just give your H ammunition to hurt and punish you further, then maybe you wanna hold off on that.
Have you read “Passionate Marriage” by David Schnarch? If not, you really should. Self validation is all about weathering these storms, not basing your sense of rejection on another, and all for the very purpose of not falling into the defense cycle. Heather’s task is not to protect herself from being hurt by her H, but to learn to endure his attacks without internalizing them, then express to him in an honest and vulnerable way how he made her feel.