You get jealous of someone who seems to flirt with your partner (justified or not, it doesn’t matter). You feel uncertainty about whether your partner loves you, is attracted to you (or the other person), will leave you, will hurt you. This uncertainty is certainly understandable, relationships of all kinds are filled with uncertainty. Additional reactions you may experience -Lashing out at your partner (or trying to control them), making them feel less trusted, possibly hurt, defensive, or closed off, damaging your relationship. Learn to accept yourself the way you want. You are magnificent and should work on your self-esteem. All insecurities in a relationship stem from your own insecurities, trauma, and lack of proper self-love and which allows you to feel triggered whenever something hits too close to home.