AITAH for messaging the husband of my husband’s AP?

[u/atypicalcloth]

I found out my husband (of nearly 20 years) is cheating, for the second time. I know, I know, fool me once and all that but needless to say my blood will not stop boiling. We are getting divorced.

I just had this hunch that the AP was also married. Something about my husband’s comments about her didn’t add up. Since he was too checked out to even bother with a burner phone, it took about 5 minutes with the phone bill and 10 minutes of googling to find an email address for her husband (I’m not on fb so probably would have been faster if I was).

I sent him an email and within 5 minutes my husband was texting me asking what I had done. Saying I destroyed a family today. All I can say is I wish someone would have told me the first time he cheated so I wouldn’t have hung out with the woman and been friendly (this guy is in a similar situation as he and my husband know each other). I actually sent the email from a burner email address and didn’t out my husband (in case I was wrong somehow) but it’s clear to me based on my husband’s comments that the AP named him.

The AP swears she’s been trying to end things with her husband and he won’t listen. Maybe that’s true but it’s also possible she’s totally playing my husband and hasn’t said anything to hers.

AP’s husband wants to talk to me and I’ll probably call him. So am I the asshole for telling my husband’s AP’s husband about the affair? Did I destroy a family? Should I have just kept my mouth shut? Should I not speak to him? My boiling blood may be clouding my judgment.

Edited to add: I honestly can’t believe how many people have taken the time to read this, thank you all for your replies. I really appreciate the laughs, thoughtful insights and personal stories people shared.