It's very easy to believe that the things in our lives that happen to us or around us are ABOUT us. We assume responsibility for things that may have nothing to do with us personally instead of asking ourselves a simple question: What else could it be?
Other people sometimes act in ways that create distress in us. A go-to response for many people is to internalize the actions of other people. "My significant other had a fight with me and won't tell me why and then they stormed out of the house and they must be angry at me and nobody has ever really loved me and what is wrong with me?" might also be interpreted as "My partner was in a really bad place today. Something may have happened (...work, home, during commute, bad dreams, no sleep, feels ill...) that I don't know about. I'll let them talk to me when they are ready." Try to allow for their mood being about something that is not you. Some things might feel very personal without being personal at all. Sometimes how someone acts is fully about them and not at all about you.
What a relief, right?
This kind of cognitive restructuring is often helped by finding a professional therapist to help you recognize when you are internalizing and guide you in changing your perspective. Find someone you can trust if you can't do this kind of work on your own.