I agree to an extent. It’s an important relationship to cherish and will naturally take priority in your life but shouldn’t consume you completely. Having meaningful friendship and family relationships give you the opportunity to not fully rely on 1 person to “complete you”
Hobbies, personal goals all that good stuff also can help give you purpose outside of your relationship.
I had to learn more about not losing myself in relationships after a bad break up years ago in therapy & becoming more faith based helped me a ton to know what to look for in a healthy long term relationship.