As of the 1.5 patch you actually should be able to marry Lydia without making any changes to her in the creation kit, so I don't know why you had to do that to marry her.
Anyway, Lydia sleeps in the basemant because she's a housecarl and therefore defaults to sleeping in the housecarl's bed, even if she's married to you. Maybe if you dig around with the creation kit you can find some kind of housecarl faction (PlayerHousecarlFaction?) which, when turned off, will make her sleep in your bed instead...?
Thank you, yes I recently discovered that the bed in the basemant is marked as 'Housecarl' ownership, however, here is my strategy, I will take Joris the Sword - Maiden (the housecarl in Solitude) out for a dragon hunt, where she likely will die, then I am going to open the Creation Kit and remove the ownership of the bed in the basment, if necessary, remove it, and forge that room into something else, I'm not gonna delete Jordis from the game... just get her killed and add an alteranative mod to the game.