Honestly if it was my husband and you told me I'd be so grateful to you for your courage and morals!
The reason OP is on here is because:
She let her (completely) understandable rage against his not being straight with her in the first place get the better of her and she did something that she knew would hurt innocent strangers (mother and possible kids) in a moment of drunken abandon.
It wasn't a moral decision, it was an emotional response. And the courage was Dutch.
I'm not sure that anyone can help with the feelings of guilt and self-recrimination you have, OP.
In my opinion, you should have kept your beef with him, and never in a million years involved anyone else. But that's because I would never be so full of myself as to think it right for me to start barrelling around in other people's lives, being totally ignorant of any actual circumstances.
Which is how I think you feel, too, OP, which is why you're devastated that you let your anger take over, fuelled by wine.
You can't do anything now, of course, as you know. And you sent pics so can't even message her to say omg so sorry wrong person!! Not your husband!!!
How did you find out he was married?