So You Think You're An Adult with Barbara Scully and Declan Buckley

We received the below dilemma from a listener

Neighborly Love   

 We’re blessed with the neighbors we have. They look after our house when we’re away on holidays and we drop into each other's houses for a coffee from time to time. Even our kids are friends. The problem is that my husband was out walking the dog on the beach last weekend and he caught the woman from next door kissing another man. She saw my husband and knows that he saw her too. I think we should tell the husband that his wife is cheating while my partner thinks we should stay well clear of the situation. What should we do as it’s getting awkward when we bump into them?   Help