Fuqi 夫妻宮Zi Wei's twelve palacesZi Wei Dou Shu 紫微斗數

夫妻宮 sits three along from 命宮, and the tradition reads it with the palace opposite, 官祿. That pairing is famous in 紫微: intimacy and career sit directly across from each other, so weight moving on one side pulls at the other. That isn't a moral claim, it's the structure.

So what it reports is who you are in front of whoever is closest: which side you show, what you need, what you're afraid of. It frequently differs from 命宮, and the difference is itself information — plenty of people are one person outside and another inside a relationship.

Reading it as 'what your spouse will be like' is the common simplification. The defensible reading is that it describes the pattern of relationship you keep walking into — and a pattern, once recognised, doesn't have to repeat.