Lydia is a pain the the you-know-what.
20 minutes after she started following me, I took her out into the woods and shoved a knife into her chest.
Did the same thing with my first wife, except after killing her I dragged her body down to the river, threw it in, and watched it float away. Best day of my (Skyrim) life.
Received the news of her death and some coin from a courier as inheritance later. I guess murder does pay off

Companions and spouses are highly overrated. I like being a loner.