Since you asked, here are some major spoilers
Sovieshu accidentally ate and also fed navier some cookies during their childhood that caused infertility. He tried to secretly treat navier but never discussed anything with her and just speculated that she was infertile. This whole ruse was to get an heir but he was not only a coward but also a selfish prick who just wanted to find any excuse to get a concubine. All of the problems he claims to have with navier being cold and even the infertility could have been easily resolved if he had discussed any of it with her but he took the selfish and coward's way out and just got a concubine instead. And to answer your question, he is a selfish dumbass but his deeds will come back to bite him on the ass.
That and he is actually infertile, not Navier. So Trashta's pregnant with someone else's baby.
Oohhh I see so that's what happened (⊙…⊙ ) Thank you very much for telling me! ε=ε=(ノ≧∇≦)ノ
Hahahaha Trashta is really something, now I can't wait to see her downfall (≧∀≦)
Maybe Count Elgy? HAHAHAHAH
Spoiler
Allen
What pique my interest the most is the fact that these two (Sovieshu and Empress) are on really good terms and they are even called "Lovebirds" but suddenly their relationship became like this, I wonder if its just because Sovieshu is a dumbass or he is just not satisfied with Empress because it is said that the Empress doesn't wear her emotions on her sleeve and she's not easily pleased with the things that are given to her. But I think there's a deeper reason for it? So please SPOIL me! (￣ε(#￣)Σ