Loved and cherished come from another person. Fulfilment mostly doesn't. That one comes from work, from friendships, from something you make, from how you spend a Thursday.
Couples get into difficulty when the third gets outsourced to the first two. No single human being can be a career, a community and a purpose at once, and asking them to be is a heavy thing to hand somebody you like.
The good news is that it takes pressure off. A relationship does not have to carry your entire life in order to be excellent.
Where does the third one come from for you? It is worth being able to answer.