What would you do if you knew a family member's dark dirty secrets?

[Lorelei]

My Aunt J has been married to my Uncle R for 20 years now. They have 3 children together.
My Aunt J had an affair with a neighbor man (her only affair) a few years back. She felt neglected by her husband so, she sought comfort elsewhere.
When Uncle R found out, he obviously blew a gasket. He agreed to stay with her if the affair ended. The only problem is now he makes her feel like crud and plays on her guilt.
I know some secrets about Uncle R though. Many years ago he asked my other Aunt (his wife's sister) to go on a business trip with him. Code words: Have an affair with him.
I also know that when he is abroad in Europe, that he visits prostitutes. I have seen this with my own eyes.
What would you do in this situation? Let Aunt J know what her supposedly innocent lovely hubby is doing? Or keep your nose out of it and continue to let Uncle R guilt trip your Aunt?
Thanks!

[E Z]

Your Aunt deserves to know what's going on, especially when it comes to sleeping with prostitutes in foreign countries.

[Yahoo Advice Lady]

Talk with your uncle and let him know that you are aware of his visits on prostitutes and ask him to stop harass your aunt. I guess this is the best way to solve this issue.

[maral b]

wow i know ur feeling honey,
u should a warn ur Aunt &tell to ur uncle..what a bad relation.

[Beth]

Keep out of it. Remember, what is done in the darkness, always comes to light.

Let the flow of nature take its course. Sit, watch and wait. Life is full of surprises.