Gilfriend gets upset at boyfriend for letting his friend come over for "boardgame night" with his new girlfriend, and she thinks that is breaking a boundary: 'This is the first time it happened, so I didn't know that we have this particular "rule"'

Maybe your girlfriend IS acting extremely toxic… And I promise you that is not good. 

Relationships are weird, because imagine being one full year together and then discovering that your girlfriend is actually extremely toxic and insecure. Some people shouldn’t be in a relationship. I don’t mean that they should remain single forever. But maybe instead of focusing on finding a couple, they should be concentrating on bettering themselves and forming a better relationship with themselves and their self-esteem before jumping into a relationship. Not everyone is mentally prepared to accept an adult relationship, because part of it includes not acting like a teenager after every minimal inconvenience.

Jealousy is the way our brain demonstrates our own insecurities. Thinking that your boyfriend is cheating on you, whether it is true or not, is a representation of our own fear. The inside thought behind the pure jealousy is the fear that we are not enough, that someone better is going to appear and our lover will leave with them instead of staying with us. This kind of train of thought can have different motives. It can be that your couple is shady or isn’t proving/showing you how much they love you, which makes you think that maybe they aren’t fully interested in you. Or maybe it’s just a representation of the fact that you don’t even like yourself, so you don’t fully believe that this person loves you.