In the case I described, it's just meanness. She has confided in me that it's been a problem their whole marriage....actually breaking them up for awhile. (their in there mid 50's.) That's what makes it even more uncomfortable for all around. She always looks like she's going to cry...and I think he enjoys hurting her. It's making my husband not like him either. Individually, they're terrific...but together??? Sigh....
That's sad.