After married, I prefer not to stay with in-law. 1 week meet once, relationship is better than meet everyday, has lesser conflict because we are all brought up in different environment.
When there are any unhappiness between the MIL and DIL, during this time, son/husband must be supportive. Listen to their complains silently and not add in more salt and don't go and tell ur mother or wife that so and so complain about you, this will add in more fire. Sometimes when mother and wife complain is they want to let go their 'steam' only, after letting go, they might get back to normal again, so if the son/husband tell his mother/wife that so and so complain about you, then when both party meet together again, they will be paiseh, this might worsen the relationship further. These are my
. White lie is no crime.