I have done a search and Thread Subscription seems to be an issue, but i cant find the answer to my question.

How do i turn off auto thread subscription?

I delete the subscription, but the next time i post in that topic it auto. subscribes me again.
I know this can be turned off, because in User Options it says:
"When you post a new thread, or reply to a topic, you can choose to automatically add that thread to your list of subscribed threads,"

Anyone know how to do this?