whyme2014 -
Please, please speak to your solicitor TODAY about getting an anti harassment order on this man.
You may wish to tell your solicitor that you want to raise a formal complaint with your ex's superiors about his personal behaviour.
You mention about entertaining prostitutes - I don't know if that's you exaggerating and venting steam, or if that's something you have evidence for.
But you NEED to be getting a formal complaint to his superiors. This man is in a position of authority, and the police take things like this seriously. It taints the authority of the police, and brings their reputation into question.
Please compile all the evidence that you have - him cancelling utilities and taking the credit from the joint account. Him transferring your details to a new car (that he shouldn't be allowed to do). Copies of the aggressive texts that he has been sending you. Any threats. Any harrasment. ANYTHING.
This is partly about getting back at him, but mainly it's because a man like this should not be in a position of authority - especially one that involves handling firearms.
I think you also need to sit down and have a frank word with your daughter. You aren't going to benefit by taking the high road here - she will naturally believe the person who sounds like they are telling her the gritty details, rather than glossing over everything. You don't have to stoop exactly to his level, but you need to be honest about your reasons. Too often the wronged parent takes the high road, and thinks they have to be a constant pillar of strength for their child. So the child sees one parent "really sad and distressed and blaming X" whilst seeing X as "calm and composed and cold towards Y". So naturally they believe the lies they hear.
There is nothing wrong with showing your child that you are struggling too, and being honest. 11 years old is too young for the cold harsh truth, but you can tone the language down.
For example:
I know you are upset because you haven't seen Daddy in a while. I know Daddy has been telling you that this is because I am preventing you from seeing each other. I haven't been talking to you about this, because parents should never drag their children into their arguments - but now it has got to this point, I want to tell you the facts about what is going on. You don't have to believe me, but I don't deserve to have my own child resent me because they only know one side of the story. So here is what is happening.
Your father decided that he no longer wanted to be a part of this family, and that he was leaving. This was HIS choice. He has been having an affair since July, which I only found out about recently. He has told people that I have been violent towards him (which I haven't), which means that I can't be in the same place as him without other adults to witness how we behave towards each other. We have both been speaking to lawyers, which is normal and necessary when two people separate. Our lawyers have said that the only thing your father needs to do in order to see you is to speak to me a few days beforehand to say he wants to see you, and for us BOTH to agree when this will be and for how long. That is it. What your father has been doing is TELLING me the DAY BEFORE that he WILL be taking you at a certain time. I can't allow this, because it goes against what BOTH our lawyers have told us. But of course, it works very well to make him look good and me look bad.
No-one is happy in this situation. This is the worst thing I have ever gone through, but I have been trying to be strong for you, because I love you. I can prove that everything I have told you here is the truth. I have been trying to protect you from our arguments, because I don't want you to feel like you have to hate one of us. We are both still your parents, and we both still love you.