I agree. Moving is job one, followed by legal name change (change the kids names too), followed by complete disconnecting from social media, followed by going off the grid for a bit, lay low for a bit. SSA will let you change your social security number in situations like this. If it’s a life and death matter, this is how you’ll have to do it.

Edit: Also consider hiring a private detective to see if the person is actually doing serious physical stalking, or buying things like guns.