My wife had a great idea for family merging through marriage. Surnames would change to be hyphonated (Durio and Paves surnames would be changed for both to being Durio-Paves and Paves-Durio respectively), and certain perks could be implemented. Hunting together might allow a +5% xp buff. Maybe you can gift each other 1 item a month. Shared home benefits from the marital bed. A concurrent questline that requires your partner to do one thing while you do another.

And if worse comes to worse we can register our wives on the breeding market, or exchange them altogether....

Faultline runs away