Ok...I hope I don't get in trouble for going off topic but here it goes.
Zenaida and Felix did have two seperate bedrooms and granted that Felix did have a staircase that lead to her bedroom, but who knows how often he used it. Also, one must also remember that some time ago Greg King posted that there had been some information that stated that Felix Sr had a male lover. Okay, this could be just rumor, but you most also think that perhaps he did have a lover on the side to turn to when he realized he couldn't turn to Zenaida, since she couldn't risk having children. Then again perhaps they had birth control of some sort, but then this is all specalution which leads me back to only known fact here, Zenaida knew there would be no more babies after Felix.
They did have a relationship which although odd to some, seemed to work for them. By all accounts they were devoted to each other, and Zenaida did chose him over all other suitors, and believe she had more than enough suitors to chose from. Although Felix wrote that his mother would perhaps have been happier with a different sort of man, I don't think she was miserable in the marriage, but perhaps not as fulfilled due to their different personalities.
Here's another thing. Zenaida may have known that Felix would be her last child, but she must have also feared attempting for another one because not only was her life on the life, but the added anxiety that even if she and the infant lived, that the 'Yussupov' curse may take her child away later on. This seemed to be a fear she appeared to have for both her surviving sons, therefore had she had more children, more than likely she would have been suffering over the possible fate of each child. Sad situation all around, and in end she only ended up with one son living past 26.
