You don't own your significant other. I think this is a common misconception in relationships nowadays. You are in a relationship, but that doesn't mean you own them. Your significant other has thoughts and feelings that they keep to themselves. It doesn't matter if you think you share "everything", there is some stuff that you know nothing about.
Being jealous isn't something you should be proud of. When you're jealous, it means you don't trust the other person. You have no right to go through their phone. It doesn't matter if they consent to you looking through their phone, do not. Your significant other is allowed to have friends of the opposite sex, and they should be able to not have to worry about you getting jealous.
Why is it that we are so ashamed to be attracted to someone else while we are in a relationship? Being attracted to other people is not a crime. I read a quote the other day that said "True love means that it is IMPOSSIBLE to be attracted to others." I laughed when I saw that quote, because it is unrealistic and false. Unless you are demisexual and only feel attracted to those you have created mental or emotional bonds with, you will always feel attracted to other people, even in loving relationships. So, don't get mad at your significant other for being attracted to other people. Sit them down and talk to them like an adult, and clear the air.
One important thing you need to remember is, spending time alone is important in relationships. Don't get upset because your significant other doesn't want to be with you 24/7. People naturally need space. You partner is allowed to do things with you, and they shouldn't have to fear you will be mad at them because you didn't invite them. Give your partner time to be their best self and to be open and honest about it.
Being a "crazy" significant other isn't something you should be proud of. Being "crazy" doesn't mean you're in love. I see quotes all the time that said "If your girlfriend isn't crazy that means she doesn't love you." If you need to act crazy in a relationship, because you don't trust them or because they caused you pain somehow, then you need to end the relationship.
"I'm not jealous, I'm territorial. Jealous is when you want something that's not yours. Territorial is protecting what's already yours." I hate this quote because your significant other isn't something you claim. They are not a piece of land or an object that you can claim dominion over in the name of a relationship. They are people. Once again for the people in the back; YOU DON'T OWN YOUR SIGNIFICANT OTHER.