Why was the Garden of Eden called Paradise? Because neither Adam nor Eve had in-laws!
Growing up watching sitcoms, I observed that the biggest nemesis to a sitcom spouse is his or her mother in-law. These yentas always find ways to crawl under the skin of their sons and daughters in-law, criticizing cooking, making off-color comments, and suggesting that they are not quite good enough to be in the family. The main take away from this culture: stay as far away as possible from your in-laws' house! The Talmud advises otherwise!
In chapter five of Masechet Ketubot, the topics focus on vows that a husband might make concerning his wife; in Ketubot 71b, the Mishnah describes the scenario of המדיר את אשתו שלא תלך לבית אביה... A husband who vows that[he and] his wife will not go visit his in-laws
The Mishnah condemns any such statement, and encourages a husband to permit his wife to visit her parents at least once a month if they live in the same city. And if they reside in different cities, at least on one of the three annual festivals (Shavuot, Sukkot, and Passover).
The legal discussion seems to be driven by the age-old aversion of husbands to see their in-laws. Despite a husband's protest, the Jewish tradition here emphasizes the importance of a wife being allowed to visit her parents on a regular basis. The rabbis viewed prolonged deprivation of familial love as a cruel act that warrants divorce.
The issue of parental visitation might not serve as grounds for divorce nowadays, but it surely matters in regard to healthy relationships. As a recently married couple, Stephanie and I have already worked out a system for splitting up the holidays. We visit her family for Thanksgiving and Hannukah (and whenever we happen to be in the Boston area), and my family for Passover, and for regular dinners (we live about 25 minutes away). Despite our seemingly workable system, visits to our respective in-laws can be emotionally taxing.
Stephanie and I both enjoy our own respective family dynamics, but it's sometimes hard to fully appreciate each others. In my own life, my parents have proven that in-laws become an important part of their partners' lives. I watch as my mother treats my paternal grandfather Poppi with the same love and care that she treated her own father. This is the kind of ideal relationship to which I think the Mishnah is hinting!