I just found out that my brother cheated on his girlfriend. They were together for almost a year and she seemed like a really great person. I know she was cheated on by a previous boyfriend and it basically crushed her. I feel so bad for her, thinking about how she must be feeling. I am in complete shock that my brother would do something like this. I thought he was way more mature than that.

At the same time, he’s my brother, and he’s very insecure (which I’m sure has something to do with his actions). I know it isn’t my business, but we’re very close, and I’m worried it’s going to come up…I’ll have no idea how to act. I’m afraid of making him feel any worse than he probably already does about hurting his ex (what he did was messed up, but I know he cares about her and is almost definitely hating himself right now…)

Please, tell me what I should do if he tries talking to me about this?