If what gets on the bedclothes is Mani (sperm) that is not mixed with any other secretions, then you do not have to wash the bedclothes. But if what gets onto the bedclothes is Madhi (prostatic fluid) or some other secretion that comes from the private parts of the man or the woman, then you must only wash the spot where this fluid got onto the bed.

Everything that comes out of a woman is impure apart from the maniy. Every other substance that comes out of the two passages is impure and breaks wudu.