Throwaway because my family knows my main. I (30F) am torn and honestly kind of shaking while writing this. My brother “Jake” (28M) is getting married in two months to “Rachel” (26F). (Fake Names) On the surface, they’re a picture-perfect couple. She’s sweet, smart, very put-together, and completely in love with him.

Here’s the problem: Jake cheated on her. Multiple times. And I know because he told me. Drunk. At our cousin’s wedding last month.

He started off venting about “cold feet,” then casually dropped that he had “messed up a few times” during their relationship, but it didn’t count because “they were on breaks” (they weren’t), and that “Rachel would never find out anyway.”

I was stunned. I pressed him on it the next day when he was sober, and he doubled down. Told me it was “years ago” (it wasn’t — one time was apparently just last summer), and that telling her now would just “blow up his life over nothing.”

I asked if he planned to come clean. He said no. That he loves her, and he’s a “different person now.” But here’s the thing — I’ve heard that line before. Jake has a history of being shady in relationships. He always gets away with it because he’s charming and people don’t dig.

Rachel has no idea. She’s literally planning her dream wedding while he’s sitting on this secret. And now, I’ve been invited to her bridal shower. I’m close with her — she’s basically family already, and I actually like her more than I like my brother most days. We’ve had deep talks. She’s told me how scared she used to be of being cheated on because of stuff in her past. How Jake made her feel “safe for the first time.”

So now I’m stuck.

If I go and pretend everything’s fine, I’m complicit. But if I say something — especially at the shower — I’ll be blowing up their engagement in front of her family, friends, and people who probably already paid deposits. My brother will never speak to me again. My parents will 100% take his side. They always do.

But if it were me... I’d want to know. I wouldn’t want to marry someone who lied to my face while everyone smiled in the background.

Would I be the asshole if I told her the truth?
And yeah, I know the timing sucks — but maybe that’s the point

(Not sure what I’m going to do. Shower’s next weekend. If anything happens, I’ll update — though it might get messy.)