I too think you're afraid of being a single mum, which you needn't be. This is based on several comments you've made but particularly asking a pp who'd left their relationship if they'd since find a nice partner.
I've been single to all intents and purposes since leaving dds dad for infidelity, I've dated but not met anyone that I wanted to get serious with. I'm actually perfectly happy being single at this point it would take someone absolutely awesome to persuade me to get into a serious relationship now.
In terms of the children, dd was very young when we split and ime that is best for dc regarding splits. Not only dd but also other dc and families I know who've gone through a split, the older they are the harder it is.
Dd doesn't even remember her dad and I being together, her normal is the 2 of us being a family. My closest friend has a similar experience, her 2 were very young when she left her ex, he never bothered after the split, she has since met and married someone utterly lovely and the dc call him dad and adore him.
Others where the families split when the dc were late primary or high school age, the dc found it much harder to adjust. And that applies no matter how good/bad/indifferent the dad is/was.
Although on that note I would also say that of the "categories" of how ex's behave as dads the hierarchy in terms of what's best for dc is as follows:
Engaged, involved and loving dad
Deadbeat who vanishes from their lives
Deadbeat who uses them as pawns to mess their mum about, haphazard contact, unreliable regarding cm, bad mouthing mum to them
The last one is one you really don't want in their lives and it's best not to goad them and to just grey rock and let them eventually also disappear from the dcs lives
@user18467425798532 is absolutely right too. His behaviour - and your acceptance of it IS damaging your dc NOW. I know you don't want to hear that but it's true. There is a wealth of evidence for this too.
I too am from an abusive family and I certainly have memories of the controlling and abusive behaviour of my dad and my mums lack of action from a very young age, probably 2/3 years old. As do my siblings.
My mums inertia now means she is his carer, she very much regrets not having left him decades ago. We dc used to beg her to do so. There are certain aspects of his abuse that wouldn't have happened to me if she had left when we were little, and thinking about it that's true for my siblings too though they experienced different abuse to what I did.
It's one thing deciding to put up with his treatment yourself, it's quite another making that deciding for vulnerable children who have no choice in the matter.
He's not "immature" he is actively choosing to be controlling and cruel.
Also counselling is the LAST thing you should do. He is exactly the type of abuser to take anything you disclose in counselling and using it against you while simultaneously not disclosing anything of use to temper his behaviour. It's never advised where there is abuse anyway and this is abuse. I think you are in denial about that.
My dad is abusive in every way you can think of though the physical abuse is now no longer possible for him. By far the most effective abuse and the hardest to recover from is the mental/emotional. By a very long way!
You can tread water until you're practically ready to leave, that's sensible, especially as many abuse victims return to their abusers because they have issues with housing etc so plan and prepare (without his knowledge) but once those plans are in place, you really must leave. No excuses.
I know that's not what you've asked for but it's genuinely what's best for you and the dc.