Codependency issue: my partner told me he needs “alone” time

My partner and I live together. We work at the same firm, mostly from home, my partner goes to offline team meetings only once or twice a month. As we share both private space and work space around the clock, it almost feels like we share everything. We’ve been together for 3 years, and lately we’ve been arguing a lot. I don’t know if it’s general tiredness or something else, I don’t want to think about it. I want to fix things between us, and I need to do it quickly because we’ve talked twice about breaking up now and it’s not healthy. My partner suggested that we intentionally spend less time together. It means working from coffee shops twice a week for each of us and spending one weekend separately. He bought a gym membership and renewed his old school friendships to play football on Sunday evenings. I’m supposed to do something similar, like have a night out with girls or walk in the park. The problem is I’m an introvert and I’ve detached myself from my friends since we started dating. My partner was my best friend and I didn’t feel I needed anyone else. He is my whole world, even though I realize it’s childish to depend on my partner to make me feel happy. I know I have codependency issues; I always had them at school and later. I feel lonely and lacking validation when left on my own. I need to feel attachment, and a part of my mind always hopes that someone’s going to come and save me. From everything — boredom, illness, myself… My SO was, is such a superhero, comfortable to be around with even when we’re silent. He is my person to relax with, I don’t think I feel the need for friends. I’m afraid we’ll have less quality time together now that he’ll spend more time going out and seeing other people. Damn, I’m ashamed to write this, but I’m afraid he’ll meet someone else, someone better than me. It’s ridiculous, he has chosen the gym and football specifically not to increase the tension between us, and here I am crying about dangers that aren’t even real! I want to make sure we get the most of our own time and yet I’m anxious to have that me time and can’t focus on anything else but my relationship 😢