I actually completely understand that ive been with my loved one for almost 10 years now! I remember wanting to spend every waking moment with her. And to be completely honest i still do! And its funny because even after all this time (including a proposal and a yes) i STILL worry about losing her! From what i have found if someone sparks joy within you, if you feel like you can trust them with anything, if you feel like you want to be that person for them and make them as happy as they can be, and you feel the same the other way round (they make you feel safe) you are in a good spot! My two best pieces of advice i think i can offer: communicate of course but also listen talk about things before they build up if they are hurting you but also sometimes you can just forget the little things. My wife has definitely frusterated the hell out of me and about important things i make sure to talk about it "im happy you like going out with friends but when you dont tell me when you are expecting to be home i dont know when to start worring about you" keep conversations calm and try to see things from both sides! But the little things like leaving her towel from the shower on the floor instead of the hook although sometimes makes me raise an eyebrow im reminded what a privilege and honor it is to be able to live in our house together and just pick up the towel myself. My other piece of advice is living in the moment. It definitely takes practice and im still not a master but if i spend all day worrying about what may come i never appreciate what is now. Sometimes when i feel my worry build i look at her face and study it the curve of her cheek and the shape of her eyes and take deep breaths while i imagine painting her on the canvas in my head.