If you really are jealous, maybe you are subconsciously trying to sabotage her new found happiness.

People who truly are ok with others don't try to change them. On some level you disapprove of her lifestyle. I think you should examine your own reasons for trying to control your sister. And I think you should realize that you don't need to have a partner in order to be happy. i know this concept is completely foreign to a lot of people, that you can be single AND happy, but it's very possible!

I'm on the flip side and honestly think it's sad when people are dependent on others to make them happy and are miserable when not "half of a whole". I think this points to hidden unhappiness within and seeking others out to "fix" what is wrong inside.