It's more of an 'are WE being unreasonable' really.
DH and I get on far better with my parents than his. We don't live near either of our parents but we see mine every couple of months at least, and go away with them occasionally too. We spend time with them because we get on well, share interests and sense of humour, not just out of a sense of family duty. OTOH we see his parents less because we just don't get along, don't see eye to eye on much at all (esp DH and his dad - lots of tension and arguments) and every visit is just depressing, tense, awkward. BUT they are basically nice people, and I wonder whether we are being unfair to them, because I'm pretty sure they'd like to see us more.
So is it unfair to them, or is it just a fact of life that people will spend more of their free time with people they get along with than those they don't?