Jesus H Christ! What is the world coming to?! You know Salalex, I would tell his mum the whole story because not everyone is as saintly as they make out to be, she may well have made mistakes in her marriage too, and she is more likely to be on your side if you are open and honest with her straight away. I do hope dh doesn't read this, but his mum and dad have been married 50 years, she is a Catholic, goes to Church and can come across quite traditionalist, but it is common knowledge amongst a few people that she has had an affair - you really wouldn't think it if you met her! So every family has their secrets and I wouldn't be surprised if his mum doesn't confess a few to you too.
As for him - well that's just bully behaviour isn't it? Does he think he can justify one crime by revenging it with a worse one? Would he treat his daughters this way? Or allow them to be treated like this by boyfriends? Easy to blame you for everything that's gone wrong, easy to hit you knowing you can't fight back, easy to verbally abuse you - what a bully! Seriously, talk to his mum, she might not like what you have done but she'll like what he has done even less, she is a woman too, would he advocate his father treating his mother like that?
I think you have no other choice but to come clean, or he will do it for you. But no marriage is perfect and I think you will have the sympathy on your side, you didn't have sex with anyone did you? No affairs? Just telephone talk, big deal! I bet loads of people have done that - one night stands, the lot. You sound strong, in spite of what he has done. What you did was not so bad, just keep telling yourself that, it really wasn't. How many wives have come on here complaining that their men visit internet porn sites and chat rooms? You have nothing to be ashamed of, he on the other hand should be hanging his head in shame, instead it sounds like he is actually proud of what he did!
You are so better off without him. I really would consider going to the police, so they can put an injunction on him to stop him from going near you. He may not get sacked, as it would be classed as 'assault' not necessarily a sackable offence at work, and your daughters need not know, unless he told them. They need protecting too, God knows what he is telling them! He needs a shock, to know that he cannot get away with this.
But this is your decision. Please do look after yourself and your children.