Sorry, Myrrh, but if you did that you'd only be trying to run from yourself... and I have news for you, girl: it does not work.
You cannot run and make it go away by starting another R that will magically 'cure' all your wounds. OK, you can do it, but what will happen is that you will repeat in your new R the same dysfunctional patterns that got you and your H to this point. And you will ot know how to deal with them any better than you do now. So you will have two options: fix them or run away again and restart the cycle. In any case, you will be hurt again and you will hurt your new partner and your son. The bb is full of people whose spouses never learned that lesson... they and their families are paying for that in blood and tears...
And if you are going to fix those patterns, why not try now and give your son's family a chance?
The mature way out is to analyze yourself and your R and learn from your mistakes so that you are not condemned to repeat them. If that saves your M, great. If not, you get a divorce, mourn properly your lost M and then you'll be ready to find someone else for real. You'll be a more mature and better person for all you have gone through. But there is not such a thing as the magic pill that fixes a R...
Just thought you needed a reality check...
"You don't throw a whole life away just 'cause it's banged up a little"
Tom Smith in "Seabiscuit"