Rose,
It sounds like your husband is not just relieving his tension...he his relieving himself of responsibility. He throws it out there so you might feel guilty or sorry for him. My husband does that alot and it annoys me to no end. I don't have an answer for it accept that I know my own mind...he may THINK he is playing me but I know he is not!
You are becoming more aware by leaps and bounds. A year ago you would have felt guilt over your sister's comment. Today you are mad...that is progress. As you learn to act differently your sister may too.
Hugs,
JT