I don’t understand how people can be sensitive to little things and still want to dive into open relationship.

Honestly, if you want an open relationship keep your emotions out. Emotional attachments in open relationships can lead to more dangerous problems. So if you feel jealous even a tiny bit of it, just know that open relationships aren't for you.

We can't control who our hearts fall in love with. If your partner ends up falling in love with the other person, that can leave a more devastating heartbreak.