FWW here, hope you don't mind me commenting but your post struck me.
Of course you need to protect your heart, it is precious!
You actually sound like you are in a healthy place if you don't feel frightened and desperate to stay married. You are right, you would be Ok. Which means you can be true to yourself and your feelings and your WH has to suck up his own anxiety and keep working on himself and becoming the man he wants to be, for himself. There is a big difference between WW's just being 'good' for a bit and whining when their/our good efforts aren't being applauded and the pats on the back aren't forthcoming, to the WW who is continually working at their Why's and why they/we use terrible/destructive coping skills instead of healthy ones. That is an on going path of learning and growth.
So yup. Right now this is how you feel, but also know, that with time and true remorseful consistent actions from your WH that this too can change for you. As well as your own growth and change through this.
And if doesn't, then perhaps different decisions need to be made.