Sometimes such kind of jealousy could be harmful because sometimes the co-worker could do something that might be harmful to you in the first place. In such case, it is important to discuss this thing with the employer.
This is actually one of the reason why I always like for things to go normally the way they expected to go in any business organisation that I'm working. This is because people can actually go to any extent to deal with you if they believe that you have taken away something that rightfully belongs to them.