OP, I find this to be the weirdest discussion in so much that there is SO MUCH DISCUSSION about this.
Accusing you of being bitter or jealous...
jealous of what? Bitter? For what, finding out that he's married?
Accusing you of destroying a family, traumatizing (possible but non-existent in this case) children...
No, he is ruining his family. He is the one who is soliciting other women and sending them unwanted dick pics, he's the one destroying his family, not the unwanted source of attention.
But "sending a postcard was attention seeking"? Or that somehow this was going to give him a turn on? That you going through the trouble of getting a postcard and putting his address on it putting a stamp on it and putting it in the mail was somehow validating that you're ga ga over him and that makes him feel like a big man?
Oh ffs!
You did the detective work to find out his address and name as he gave you the information... And by sending a postcard, anyone else who happens to glance at it will know his dirty business.
And if people are arguing that what if the post office accidentally delivers it to the wrong house, you're going to ruin somebody's life? Hello? It's got the guy's name on it. What if I was accidentally sent the wrong piece of mail to my house that had somebody else's name and address on it that said that I had a serious disease, and I go what? And then I look and I say oh that's not me....
Honestly, what you did probably gave you a sense of "take that, you wanker" empowerment. And why the heck not.
I don't know if going to the police will solve anything, I didn't really commit any type of major crime, this is really more of a nuisance crime, and more than likely police are too busy for this type of thing but, if you think you'll get somewhere with it, teach this arse a lesson...
In a perfect world, it would go on record that he's been sending unsolicited sexual images to women, so he'd have some type of record, as he said there were no children there really are no children involved, and his wife who may not have known what kind of a scuz this guy is, at least knows.
And, although unlikely, in a perfect world the mailman would read the postcard, and then tell all the friends and neighbors what a jerk this guy is then the entire neighborhood turns against him.
Highly unlikely and unprofessional but hey, one can always fantasize.
I don't think what you did was bad. In fact, I might have done the same thing. But there's certainly are a lot of opinions out there that this wasn't the right thing to do and I'm just really surprised by that. But everyone's entitled to their opinion. So I wanted to share with you, mine.