I don't have a problem with people feeling some jealousy and dealing with it. I think it is healthy to look at/resolve/come to terms with any feelings that overtake us or upset us. However, jealousy... ugh. It's a sore point with me. When I was younger, I had boyfriends who were so extremely jealous and possessive that it tainted everything. With one bf I was with for a few years, if I turned my head to look out the window while we were driving through town, he would snap "who are you looking at?!" and I had to keep my eyes focused up front. He judged what I wore based on who would be checking me out. He wanted me to look appealing but not too appealing, for fear I would be stolen away, I suppose. Things like that made it hard to socialize and only made me more shy and awkward. This was when I was really just budding as a sexual being and learning how to relate in groups.
Now that was extreme, and I was young and not yet fully my own person at that point, so maybe it scarred me a bit, but through the years I have come to observe that, although we all experience jealousy and envy to some degree from time to time, jealousy isn't all that healthy for loving relationships. That's just my opinion, which I reached because I've seen very often how jealousy is easily connected to insecurity, possessiveness, and competitiveness. I have had cases where I wanted to stay friends with an ex but his new gf wouldn't allow it out of jealousy. I just think that is sad.
I never objected to my ex-husband having women friends or staying in touch with ex's. I was rarely jealous because I was very secure in our relationship. When I trust someone and feel secure, jealousy doesn't come up for me. It was only after my ex-h told me he wanted a separation that I started feeling jealous and wondering which women at his office he was socializing with, because obviously my sense of security in our relationship had taken a major hit.
I see jealousy, for the most part, as a self-manufactured state of being that comes out of thoughts we entertain and indulge in, and/or fears and insecurities we don't want to look at, rather than a natural emotional response that is organic, like sadness or joy.
I think that envy is much more common, and it makes sense to me that people want what someone else has, but most people confuse envy with jealousy. I think jealousy can really mess things up. I don't want to start a relationship with someone whose answer to that question on OKC says that he believes that jealousy is healthy. It's not always a deal-breaker if other things he says in his profile indicate that he can rise above jealousy, but when it comes to men in relationships, I equate jealousy with possessiveness and I don't want to be in a relationship with a possessive, jealous guy.