u/punkrots

So my brother cheated on his wife in December 2025 at a Christmas work party, she found out in Feb 2026 because he fell asleep with his phone open and she saw that he was sending 'I love you' and 'miss you babe' in Snapchat to this girl, chaos ensued and she kicked him out to our mums house.

Next day I go over and ask what happened and he admits to me that it's true, he told me that they had sex (UNPROTECTED I MIGHT ADD!!!) I immediately mentioned that could she be pregnant?!?! and in his words "Nah it's been a while and I was drunk so I couldn't finish", I asked if his wife knew he said to me and my mum no and that he can't ever tell her because it'll be the end of the marriage for sure.

[Some info for context:
- They had their first kid in Feb 2025, the baby is a really poor sleeper, possibly lactose intolerant (so extra fussy) and I think they've just really struggled adjusting to parenthood, lack of sleep, lack of intimacy, ya know.

- They're now both in individual therapy & marriage counselling because of this cheating]

Fast-forward to this week, I guess they're trialling a separation, he said he wants a divorce but she wants to try make it work, he's moved back into mums for a month with the hope that 'the break will bring them closer' and said he'll drive down to help out with day care pick ups and stuff like that.

I'm not sure how many people he's told the full story but seeing my sister in law fight for her family to stick together while taking on the full responsibility of a just over 1 year old while my brother has moved back with mum for a month having a much smoother ride makes me just want to tell her the truth ASAP.

She deserved to know the FULL TRUTH, there's no way she'd stick around if she knew, I feel it would save her heartache and make her choice a whole lot easier. But my only issue is I don't want her to know it came from me, if it came back to me I think my mum and brother wouldn't want anything to do with me, as selfish as it sounds.

Open to advice, really anything!