brother's affair

I recently learned that my brother and his wife are separated because he'd had a fairly lengthy affair (4 months). I am devestated because I had always looked up to him. I really like my sister in law and they have great kids. I suspect it will end up in divorce and it angers me greatly that his poor choices will effect our entire future of family gatherings. We want to keep close to his wife but they live in another state and it will be less than easy. I just wish he (and others like him) would have realized before the affair how broad the implications of his actions were. Our whole extended is hurt and frustrated.

I'm assuming you will stay in touch with the brother since he is the blood relative. I just hope you can and will maintain steady contact with the sister in law and her kids. Ok, so she is no longer married into your family, but you can still consider her a close friend. That can be enough to keep the relationship alive for a long time.