You chose your partner. You did not choose your partner's parents. This single asymmetry generates more of the texture of marital life than almost any other and is treated, in most social scripts, as a footnote rather than the central fact it actually is. Romantic partnership is the only adult relationship in which one is expected to accept a permanent secondary set of relationships, with people one would never have selected, as a condition of the primary relationship. Friendship does not work this way. Colleagues do not work this way. In-laws are sui generis: an unchosen, permanent, intimate, and consequential relational obligation acquired as a byproduct of love.
The mistake most newly married people make is treating in-laws as a continuation of the courtship. During courtship, you performed civility toward your partner's parents because the partnership was new and you wanted to be liked. The performance was sustainable because it was short-term. After the wedding, the performance has to give way to something else, because the duration is no longer finite, and what you can do for a weekend you cannot do for thirty years. What replaces the performance, ideally, is a real relationship, with its own texture, that does not depend on continuous effort to fake warmth that is not there.
Whether this real relationship is possible depends mostly on factors outside your control. Your in-laws may be people you would have liked anyway. Your in-laws may be people you tolerate but do not enjoy. Your in-laws may be people whose values or temperaments are sufficiently incompatible with yours that no amount of effort will produce closeness. Each of these outcomes is common, and each calls for a different operating mode. The error is assuming that effort can produce closeness in every case. It cannot. Some in-law relationships are friendships waiting to happen; others are functional alliances that work best with structure and distance.
The reason this matters at the personal scale is that your partner is watching how you handle their parents, and the handling is being interpreted as a statement about your relationship to your partner. If you are dismissive of their mother, you are signaling, whether you mean to or not, that part of your partner is outside your circle of care. If you compete with their father for territory, you are signaling that you are not secure enough in the partnership to accept the prior claim. If you ignore their family entirely, you are signaling that the partnership exists in a vacuum that ignores their inheritance. None of these signals are recoverable by sentiment in the moment; they are read structurally and remembered.
Conversely, your partner is also watching how their parents treat you, and the handling is being interpreted as a statement about whether the partnership is being supported or undermined by their family of origin. A partner whose parents subtly disrespect their spouse is forced, eventually, to choose, and the choice almost always goes against the parents, but only after the choice has done damage to the marriage by being deferred. The in-law relationship is therefore not a side relationship; it is a triangulated arrangement in which two of three relationships are continuously informing the third.
Law 3 here intersects with a constraint nobody wants to name: not all connections are equal, and the unchosen ones require a different operating model than the chosen ones. With a chosen friend, you can adjust the relationship to your preference, increase or decrease contact, end it if it becomes intolerable. With in-laws, the exit costs are catastrophically high because exit means damage to the primary relationship. This asymmetry makes in-law relationships function more like co-workers than friends: continuing, somewhat formal, requiring competence rather than warmth, governed by structures rather than spontaneity.
The most useful frame for in-laws is therefore a kind of long-term professional courtesy with the possibility of friendship as an upside. Not the pretense of family, which sets up expectations that produce disappointment. Not enmity, which forces your partner into impossible choices. Something in between: reliable presence, basic respect, predictable behavior, modest investment, and an openness to the relationship deepening if both sides happen to find each other interesting. This frame absorbs disappointment better than the family frame does, because it does not require love, only conduct. And conduct, unlike love, can be summoned even when feelings are absent.
Finally, the geometry of in-law relationships shifts over decades. Parents age, parents die, siblings-in-law have their own marriages and divorces, and the constellation that surrounded you at the wedding will look completely different at the twenty-fifth anniversary. The investments you make now in basic competence and predictability are paying into a future in which your in-laws may need care, may become your closest co-grandparents, may become the people who hold the memory of your partner's childhood when your partner has lost access to it. This is a long game. Play it as a long game, not as a series of weekends to be survived.