Okay - so we have a problem of two halves.
-
the parenting
-
you
I'll deal with 1)
You want a reliable pattern between the three of you to be settled before your son goes to Sec. School.
You would like this to be in place (trialled) before the school year starts (and the clock is ticking)
This is of more importance than your feelings on Coward's behaviour.
The complication is your son isn't currently willing to engage with any trial.
It probably goes without saying to you, but I'll point out the obvious all the same: Your son is 11 - all he wants is his life to stay the same. So as long as he ignores the change, he will be willing it to become 'normal' again.
So the real issue you are dealing with is that you are acutely aware that his 'normal' is his 'used to be'.
So you need a) to set aside your emotions, b) to re-establish a father/son relationship and c) to have this happen before he starts secondary school.
Is this a coherent way of expressing your thinking?
The 2) He deserves nothing of you. You are hurt, angry and pissed off. You're overwhelmingly concerned with 1 (above) but you are still an adult with feelings, and you're still the woman having to manage the son, and the hurt.
On both matters you will continue to get our support and empathy. He's a coward: You want us to slag him off, we'll promise to form a disorderly queue!
So your real issue is between your hurt, your son's bewilderment, and the Coward's dictating the new future - which is rather simplistic at best.
And yet, you put yourself under the pressure of being the 'sensible' adult.
Now, why are you beating yourself up on how hard that is?