H: Since you have chosen to no longer live in our home I would appreciate it if you would not come over unannounced. In the future I ask you contact me before you simply stop by.
It is hardly outlandish to ask somebody who no longer lives in the home to call/text/e-mail their desire to come over before they just pop on by. IMO if you phrase it this way you are not telling him he can't come over. You are ASKING him not to without advance notice.
Now that you have concrete proof your H is engaging in prostitution I would divide the bank accounts ASAP. IMO you are very, very foolish not to (sorry, I am not being ugly but now that we have new information it is a necessary action). Prostitutes and ethics don't really go hand in hand. How do you know a prostitute won't steal money from your H (which in turn is stealing from you?).
Yup and yup, you have to do this, otherwise indirectly you're communicating to him that it's ok for him to do these things and you have to speak up for yourself and tell him it's not ok.
Actions speak louder than words, stand up for yourself, don't let him walk all over you, he can't respect you if you allow this.