if my ex husband were to marry again would i still be entitled to his full social security or would i have to share it we were married from 1981 till 2010

First, he'd have to be remarried for 10 years for his new spouse to be eligible under his SS credits. Second, No, at least I dont think you would have to share it.

I have been told that you would be entitled to it the same as if he were deceased, still single, or still married to you. It would be based on when you take it, not when he takes his. He would have no knowledge of what you do.