Thanks ladies. I wish I had shut it down instead of listening for nearly 3 hours! I would want to know but I honestly think she does not so I will mind my business and tell them to keep me out of it.
@Ganjababy, I think the best thing for you to do is stay out of it. I don't think you need to block them, but they need to respect your desire to not be a sounding board for either of them. Your sister and brother-in-law are adults and need to work out their issues without involving family. They are the only two people who have to live with their decisions.
@Ganjababy Yes leave it alone. I can think of several people I know for a fact are dead today behind other folks marital issues. Two of which, siblings to the bride or groom .