No one can make you feel inferior without your consent.
--Eleanor Roosevelt
Recently my aexh forwarded an email to his father and gf, in which I referred to his claiming my tax deductions, and what I did to resolve the situation.
I was mad for about a minute and a half. Then I thought: Ya know, if I'd been thoughtless enough to take his tax deductions, I don't believe I'd be sending evidence of that to my nearest and dearest.
Your ah has used the internet to advertise his poor judgment, that's all.
What he does is his to choose. How you react is not, unless you allow it to be. Be gentle with yourself, but I'm with passionfruit-- don't take on his shame. It's not yours.