Do you know OP that women leave an abusive man (on average) SEVEN (documented) times before they finally get the courage or desperation to end the relationship?
For many more, they don't get the chance. More women are killed by abuse partners than by anyone else. And often, so are their children.
To the outside world, these men can appear charming, said-of-the-earth types, but when they don't get their own way ALL of the time, they become monsters. they take out any perceived slight (at work, from friends, casual comments by shop assistants - you name it) on the woman and children they have control over. At best, they make their lives a living hell. At worst, they kill them.
You have no ties to this man - you are not married to him; your children are not his children; you do not share a mortgage; you are not financially dependent upon him - please, PLEASE, end the relationship NOW. For your own sake and for that of your DCs.
Don't think about it - DO IT!
I can understand how you may be lonely and not want to spend the rest of your life as a single person, but
A) There is nothing to say that you will be single forever
and even if your worst fears come true
B) Being on your own is better by far than being the punchbag of some controlling git.
Believe me - I've seen it in two family members. It is worse than you could ever imagine. And if he is being like this before you have committed yourself to him (e.g. moving in, getting married etc) - can you imagine how abusive he is going to be afterwards? When perhaps you are pregnant again?
Think of your children, not yourself. Don't put them through this because it scars them for life, it really does.