DH has always been close-ish to his brother who is a nice guy. BIL met and married SIL relatively quickly (no judgement from us there as it was only finances that kept DH and I marrying within months of meeting each other) and we have always been very supportive of them - hopefully emotionally as well as (on the odd occasion) financially, for example their washing machine died and we were in the fortunate position of having received a bonus, so we were able to replace it for them. I'm fairly certain that if it was the other way about, BIL would do the same for us.
BIL & SIL live in the same town as PIL, and historically have seen them regularly. We live in a different country so don't see them as often - but we speak to PIL once a week on the phone with DS and have a good relationship.
Anyway, SIL and I are friends on Facebook (yes I know!) so that she and BIL can see pictures of DS. She posted on Facebook about a major new purchase - not just a throwaway comment, her page was plastered with pictures and comments from friends and members of her family. I've also just become friends with FIL on Facebook (he's just joined) again for photos.
On the phone to PIL and conversation is on photo of DS that was posted, which SIL has commented on. MIL asks if I speak to her often on Facebook - I reply that it's more of a comment on photos thing so you don't really speak (they're still a bit IT clueless) and I mention (as an illustration) that she commented on DS and I commented on her new purchase. And the phone line goes silent.
PIL have not been informed of the purchase. Apparently they haven't seen BIL & SIL since Christmas, but BIL phoned them last week and they've borrowed some money as apparently SIL has been made redundant; and has been out of a job for a few weeks - but she's still buying expensive stuff.
Anyway, now SIL is way mad at me - she actually emailed me to vent her displeasure that "I discussed her private business, that had nothing to do with PIL" and I'm fairly sure she has blocked me on FB.
I'm not 12, so I'm not particularly bothered by this - I'm of the opinion that if it was such a big deal, she shouldn't have plastered it all over Facebook; also what the hell was she doing buying expensive stuff then borrowing money from PIL?!
But, I also don't want any problems to occur between BIL and DH, so I'm going down the bigger "apologise and make up" route.
I'm planning to respond to the email and try to pour oil on troubled waters.
But I have no idea what to say that doesn't come off as well - "grow up, and stop being a bitch to my lovely PIL"
Can someone help with phrasing this? I'd like to acknowledge that she feels a bit betrayed that I told PIL - but equally that I'm not sorry I had a conversation about something that was effectively in the public domain, especially as her profile is not protected.
Please help!