You've hit the nail on the head, m'dear. If we had the answer to the latter question, then the answer to the former would be a much-less-qualified "yes." However, the jealousy issue *is* the $64,000,000 question (adjusted for inflation), and so the best I can give you is a very-qualified "maybe."..There are some people who are less prone to jealousy than others (more self-aware? more self-secure? stupider? who knows), and you hear urban legends occasionally about open relationships succeeding for years and years. But I'm an old-fashioned gal, and I think that those are the exception to the rule. Trust is too important in a relationship, and too hard to maintain when there's more than two of you involved...

I know a couple that has been together 18 years. They can sleep with whomever they want, as long as they don't fall in love. But, they are both guys...
I know I can date a guy who is seeing other people. But in the past, I've found that I haven't wanted to be part of a harem or a hands-across-america-project. If someone really wants to be with you long term, they will commit. If you're jealous, it's usually because you care and you don't want them to be with other people. If you aren't jealous, then you often don't give s**t. (Or you know they won't do anything. But if your relationship is open, then you don't know that.)..

No. Open relationships can't exist where jealousy lives, they are mutually exclusive. Open relationships exist and have existed throughout history, some very successfully...
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I think it depends on the person. Some people can be emotionally detached from sex. Personally I get attached and would get jealous. It's hard for me to believe that eventually you wouldn't get feelings. Thats just part of something that is considered long term, you stay around that person for a reason and feelings will arise...