hi if sm1’s 7th lord (lets talk about MERCURY as 7th lord) is in 12th house and combust. rahu ketu doesnt aspect 12th house . but aspect 7th house.
mercury gets debilitated in navamnsh . does this say character of spouse is weak?
what else does it say?
As stated by you , 7th lord Mercury is badly placed and debilitated in the 12th house and 7th house is under the affliction of Rahu and Ketu. The marital bliss in the native chart is not strong. Of course other planets should also be checked and no astrology predictions should be made based upon just 1 planet.