First of all, you are not a monster. Maybe you made big mistakes and behaved bad, ok. But, there are few people who are what we can call real monsters and the only fact that you mention it, takes you away from that category.
I see lots of despair, feeling of guilty and frustration.

You only wanted to put these all out and vent in the thread and I do understand you but how in the earth, we are not gonna try to tell you something since we find your deeply sadness and you being not just hard but implacable with yourself, so palpable.

Who is your daughter living with and how old is she?
And what happened when your wife and you separate yourselves. I mean, in regards to what happen to you kid. How did she live it?

Normally, when kids have a hard time when parents split but they have also an amazing capacity for adaptation when they received and can feel the love from their parents, independently if they are together or apart.

You mentioned that you did therapy. When you were a couple with your wife or now that you are alone? I tell you because many times a therapy may not work for different circumstances but you could give it another go, for you daughter.

My apologise for so many questions that of course, which ones, I will be on your part, whether you are prepare to reply and also if you don’t reply because you are not ready or see it hard.