My cat is petrified of the new kitten... its been 3 weeks and he still hisses at the kitten and runs away?

Ok - I brought home an 8 week old kitten, and my resident cat at first didnt like him at all.... hissed at him badly and ran away, wouldnt look at me for the rest of the day.... Its been 3 weeks now and the resident cat will only hiss and growl if the kitten is near him and he is cowering down like he is very scared of the kitten.. or he thinks we are going to hit him... which we would never ever do (he may have been abused before?).... its getting exhausting keeping them apart during the day and night... its not fair to either of them to be locked in a room all day while the other is out and about roaming the house... and it doesnt help that the kitten thinks the res. cat is a toy..... and suggestions?? Thank you in advance!!