Introducing Kitten to Unspayed Male?

I have a male cat who is a year & 4 months old, he is great with my neighbour's cats and loves to play. I want to introduce a new cat into the house, but I'm worried Joey will get jealous. All I've read seem to be bad experiences. Does anyone ever have good experiences with bringing a new cat into the fold? Or do cats just like to live alone?

Also, my cat has never sprayed in my house, if I bring in a new kitten will he start spraying? Reading people's comments I'm thinking maybe it's best to just leave things as they are, but I love cats and I had 2 before who got on great. I introduced them early, when they were both kittens. I don't want my cat unhappy. Any advice would be great. Thanks.