Hope and being honest with myself
Thank you all for your comments. I just found this site today after three years keep all of these thoughts and feelings to myself and not wanting to share with family who would have said "I told you so." I thus went to the internet and found out that this is a huge problem in second marriages.
It is such a relief to realize I am not alone. I was beating myself saying "why can't I turn the other cheek?" I believe that I will get a second place like a studio and when I need time to decompress I can go there and yes my son would be more willing to visit his Dad.
With this second place if we ever had another horrible argument over the SC, she can say get your stuff and move out and where would I be. Thus I believe to protect myself and sanity I will need an exit strategy.