I'm so sorry this happened!
No, none of what he did on that online account is ethical or professional behavior! If he wanted to make an online account it should be for his clients to post on, not for him to be telling them about hisvery disturbing emotional issues! And the pornographic picture is very wrong and probably against the law!
You really do need a new t,and I've heard before how tricky it can be to find someone who is familiar with DID, but I'm sure with help from others on here or your family doctor you can find one.
The most important thing right now is for you to find a new t and to start grieving and letting out all your feelings about all this. None of this was your fault. You just need to keep yourself safe now.