How bad is it that I get jealous when I see others in a relationship?

So... I have received good, sound advice here about not putting so much emphasis on being in a relationship and instead feeling secure and comfortable with being on my own. And, I genuinely am taking that advice to heart and have already made some changes. I feel like I am on a good path. The thing is though, I become jealous when I see others in a relationship.

I guess I could repress the feeling or force it to go away through a combination of repression and willpower. All I have to do is see what appears to be 2 people in a relationship and I feel hurt, frustrated, sensitive, left out, hopeless, ugly, and unselected. To be honest, it bothers me that my inner-mind is that petty and narcissistic. I mean, these are just people I observe who are "somewhat" random strangers. Their lives don't directly intersect mine.

I don't really know what I am looking for in an answer... am I fishing for some vindication, "Oh, you're not so bad." That's pathetic, if I am. Am, I hoping someone will validate how horrible I am, "Dude, that's about as low as any human can go?" Psychologically, why would I want that kind of validation? Or, am I literally struggling to figure out what is motivating me to act in the counter-productive way that I do in an environment where the risk of being exposed seems low?