I think Dukat, before Ziyals death must have had some "childhood trauma". Parents that were not very loving, but very demanding of what he should do, very authoritarian of course, no praise for the "normal things" only for the perfect things and duty/ orders that he followed well, lots of telling him how he has to be, that he is the son of someone important and therefore is important and better too and has to reach certain standarts.
Actually most of the Cardassians we see must have had a childhood trauma.
As for his wife, I agree with those who say, it probably was an arranged marriage between two powerful families with the meaning of gaining even more power and influence and producing children, but not out of love, only out of duty. However Dukat always wanted love, though I doubt he really knows what that it and confuses love often with something else.
Adultery...I guess was not allowed, but practized anyway, as it is in our todays world... maybe even worse, if a lot marriages were arranged ones, especially in the more powerful families and especially the males.
What I just wonder, as in Cardassia children are really really important, do you think they ever developed birth controll instruments or would that be a strange concept for them?
TerokNor