I am a married person with kids. I am so honest and truthful to my husband and expect me to tell the same even if he flirts with someone. I somehow know whatever he hides. Our wavelengths are so good. He is good caring person. I see him hiding things from me and having some emotional attachment with one of my sister. When I corned he did agree and both are so dear to me that I totally trust and believe them. They respect each other and my sister is looking for a shoulder to lean to overcome her problems. Their communication is hurting me though I am sure both care for me and sure they don’t cross the limit. But I am so depressed. How should I cope up with this?

Talk to your sister about what you are going through. If she is sensible and caring for you then she will withdraw herself from this. Alternatively you may talk to both of them in joint session. It is not a good idea to suffer silently, without letting them know about it.