You have a couple of choices, but first you have to figure out what it is you really want to do. I know you feel loyal to your wife, and that’s driving your intention to tell her what’s going on behind her back. But you’re also not wanting to upset her, which is why you stopped from following your instincts, and asked me for advice.
So figure out which is better for your wife. Would she be more upset if she found out YOU didn’t tell her about this information, or would she be more upset if you decided this wasn’t your business or a big deal and let her take her journey with her friends and figure out what’s going on with them in her own time. Or…. it may not be a big deal to your wife that her friends had a party with her ex as a guest — because maybe she did know about it and declined to come and didn’t think it was a big deal, herself.
That said, you might want to consider un-friending your wife’s friends given the company they’re keeping and your feelings about it.
I hope that helps — let me know how things go, and please follow me @AskAprilcom on Twitter and on Facebook at this link: [url][/url].