I haven't experienced relationship culling myself, but I have experienced ghost culling in my game. It stinks. Madea just married a guy and he dies on the treadmill after a woohoo. But then the guy's ghost gets culled. Poor supernatural Sims getting nerfed and culled. Makes me worried about future life states too. :( Townie culling happens a lot. Like I really enjoyed this household having this grumpy maid and he gets culled. I wish I could just have their hired help and townies stay if I want them around.