Viewing your emotions as unjustified or irrational can actually prevent you from taking action to make them better. Irrational and invalid aren't the same thing. We can go wrong when we believe that any emotion that's irrational must be invalid, but we can go wrong as well when we believe that any emotion that's valid have to be rational. The latter error is made less often, but it's true that some people feel that because emotions are "valid," they must simply accept them as they are.
When rationality is very highly valued, it can become difficult to tell others about how you're feeling when you think that your feelings are irrational. Sometimes we fear judgmental responses from friends. Other times, we may trust that people will be supportive, but we still don't want to come across as someone who has a lot of "irrational" or "silly" feelings.
In this way, sometimes, people in social circles that have more traditional ideas when it comes to a relationships and communication are at a slight advantage.
For example, suppose Mary is in a traditional monogamous relationship with Bob. Mary might feel totally comfortable telling Bob that she's jealous when Bob spends time with his friend Susie. Mary might even feel comfortable expressing anger about this.
The resulting conversation might not actually be productive. Bob might just agree not to spend time with Susie anymore, or he also could react angrily and tell Mary that she's being "crazy." But in my social circles, we often wouldn't express feelings like Mary's at all. We can sometimes feel that being progressive/feminist/polyamorous/rational/whatever means we shouldn't feel jealous when a partner spends time with a friend, because that's irrational, and therefore that feeling should be ignored rather than brought out into the open.
A lot of us end up trying to ignore or cope with these feelings alone, where Bob might hug or kiss Mary and reassure her that he loves her, him and Susie constantly go out and about with each other and get ice cream and talk all the time.
The difference is that many people in traditional relationships treat jealousy as normal, even healthy, even a sign that you really love someone. Expressing jealousy in the context of these relationships can be a completely acceptable thing, like telling your partner that you're annoyed that they didn't tell you they'd be home late, or that you're sad that they can't spend the holidays with you and your family. I don't want to borrow traditional monogamous folks' ideas about jealousy necessarily, but I want to borrow their normalities about expressing it, and also expecting your partner to hear you out and respond to you with love, even if the jealousy is "irrational."
