This is going to be heart wrenching for you, you sound broken and this man has done this.
His anger through you finding out, indicates two things, that he wants to keep you and the status quo but have his side piece. You may also think that this man may up until now been faithful and is fiercely ashamed, that's what thoughts you may have but as you go through this awful journey you may see he has always been a decietful bastard, it's just you wern't looking for it.
His blatent denial of the facts shows us that this man thinks he is omnipitant, that he can tell you black is white and you have to bow to his explanations.
This man is highly abusive, and I mean highly, an evil fucker would be another term, do not underestimate how dangerous this person is. I'm sorry to scare you but many of us have experiencd this kind of man and I wouldn't be surprised if everyone thinks he's the kindest soul outside of your relationship, including your daughter.
It is important for her not to be in the company of him, he will turn her against you, it's part of his nature, he has to win, through violence, through intimidation, through hate (and he does hate you now because you know the truth) through deception, gaslighting, lies and the enivitable smear campaign that will come your way.
You will one day understand how awful this man always was but that's going to take time for you to accept. Please try not to be scared of this alien feeling of being utterly devastated that you are living with someone you don't know. Understand that this man is not capable of love, love with anyone and that includes any new squeeze he has. He's a nasty fool who will realise that no matter how he feels at the moment it's not going to last and there will be no return for him, no more cozy rooms with you and his daughter, that has been destroyed and the irony is he will blame you for that too. One day you are going to realise how controlled you have been, this man must have always had a nasty nature.
I wish you all the strength in the world to become stronger.
He's a toxic bastard who is willing to destroy his daughter along with his wife.
Do not trust him for one second and nothing which comes out of his mouth.
If you can take medication see your Gp.