There will always be one who is more strict with the kids, open to in-laws, careful with money, adventurous in bed, ambitious about career, social, self-confident, flirty, interested in a clean house, closer to family, better at math, permissive, more sharing of feelings, horny, generous to others, and on, and on, and on.
The fact that one is always more (Insert Characteristic) than the other does not necessarily indicate there’s a pathology. Just because your wife is hornier than you are, does not mean she has a sexual addiction. Just because your husband likes to clean house, does not mean he is obsessive. Pathology exists at the edges of the bell curve, where a person is rigid about their qualities, beyond all reason.
Natural variation within a couple can be an obvious source of strength, wonder, and appreciation. Two heads are better than one because they can see in both directions. Variation offers differing perspectives and skill sets.
Natural variation can also lead to discord and polarization if the couple doesn’t practice respect for their differences. Let’s just say that one partner is more strict with the kids and the other is more permissive. This will be the case with every couple with kids. Every one. If they lose respect for each other, they will begin to compensate for each other by being more and more extreme. The permissive one will let the kids get away with more because they think the partner is too strict. The strict one will lay down the law to compensate for the lenience of the other. In this way, they will get further and further apart, each undoing the other, with the kids in the middle, often helping to drive a wedge between them.
Schisms widen whenever an individual identifies more strongly with their way, than they identify with the alliance with their partner. It’s unnecessary, though. It’s easily remedied when you begin to appreciate your partner’s ways and understand how they can serve as a natural check for the excesses of your own ways.