It is unfortunate that you had to go through an acrimonious divorce and subsequently tackle the obligations of caring for yourself and your children on your own.
I certainly regret that so many human beings, particularly women, have had the pain of such events and continue to do so.
It is not uncommon for those who suffer injustice to find it difficult, if not impossible, to do anything other than blame and demean those that they consider to have been responsible for their plight.
My point is that there *is no point* in blame. It changes nothing that has happened and often clouds understanding of a real appreciation of all the factors involved. As such, it mitigates against true growth.
All human beings, in my view, are capable of the best and the worst - whatever one might consider such to be.
People who are described in demeaning ways because someone judges them to be 'evil', 'mean', 'nasty', 'disgusting', 'reprehensible', as you put it: 'a piece of shit' or any other term of abuse are still human beings. As such, they will all have some redeeming qualities and their actions a result of context, experience, mental dysfunction, conditioning or other factors. No one is wholly good or wholly bad, indeed the very terms are so subjective as to be extremely cloudy concepts, particularly if context is ignored.
However, leaving aside all the reasons why such judgments are flawed, what concerns me is that when anyone chooses to make a closed-minded judgement of another and obstinately refuses to consider any other possibility, they only increase the harm to themselves, effectively extending their victimisation, if such it has been.
Why would anyone wish to do that? I can't know for sure but I have a good idea. In most, if not all societies and cultural contexts we are taught to blame. This is counter-productive in itself but even worse when it is compounded by abusive judgment.
So, I have no doubt that I won't be able to convince you that your 'ex' is not what you choose to label them as, if you stubbornly refuse to consider any other possibility.
I also understand how difficult it is to overcome trauma, hurt, injustice and such, whether real, partly real or only perceived. To state the obvious, the mind is powerful and our perceptions are always coloured by myriad factors. However, when we close ourselves off from growth and understanding then we do 'surrender' and continue the victimisation we have endured and the hurt and pain we have suffered.
Difficult as it may be, learning from our experiences is far more productive than allowing them to dictate our responses.
I can only hope that at some time you will realise that I am not attacking or even criticising you - only expressing sadness that instead of putting the hurt aside, you are now choosing to continue it.
Take care. Stay safe. I sincerely hope that your life is filled with good fortune and happiness from now on.