Navamsa is the inner core of one self.
It represents your interest in the relationships specially marriage.
When you run the Maha dasha of 6,8,12 or debilitated planet in navamsa -It becomes very hard to find friends and partners.
As it makes you disinterested in relationships.
Specially in 8th house of Navamsa dasha running people who are looking for marriage is only because of societal pressure but if you ask them -they will tell you that -they dont have vibes or there’s no feeling as 8th house in navmasa wants you to separate as it has energy of end.
Even If you get in relationship in planet seated in 8th house of navamsa antardasha -lets suppose in venus -it will not last or lacks commitment and lot of things will be hidden as well.
If a planet goes in 12th house of navamsa and not connected to lagan or Navamsa Lagna.Then you bound to suffer isolation until planet is coming from 5th or 7th house of D1 chart.
12th house of navamsa is like more of an open relationship you want and you also tend to isolate other person so that both of you come at same energy level.
6th house of navamsa makes you fight in relationship and can humiliate you and people connected to you can also get humiliated by you as it brings abuses and warfare in marriage.
And In Debilitated planet of Navamsa Dasha you Lack Interest or We can say “JOSH” is missing.Your hormones and desires are not there and the signification of that planet also goes missing.
That is why if one Gets married in dasha of 6,8,12th house in Navamsa -its difficult to find a partner even if you are able to find someone your attitude towards them makes them run away from you and causes clashes rift and can end it at last as you are not ready to sustain it.
In such dasha you can only save your relationships by giving strength to venus and 7th lord and constantly serving and feeding the Gau Mata. As when you connect with Cows ( Gau Mata ) you will develop devotion and compassion that’s what you are lacking in Navamsa 6,8,12 dasha.
As relationships are all about sacrificing self ,devotion and showing compassion to others and to accept others as they are.
But here question is do you really have a desire or energy to save relationship in such dasha ?