That's God's Job
No human being was ever created to "complete" another human being.
Not even Eve.
She was created to compliment Adam not complete him. There is a huge difference in those roles. We get it wrong every time when we demand that someone complete us. It's rarely a spoken demand and usually an unconscious one. We don't even recognize that we are putting the demand on someone until they scream at us "what do you want from me?" It's happened to all of us at one time or another. Our frustration with a person that we are in a relationship with builds and builds until we react in an unhealthy way towards the other person usually ending in not talking to them ever again or continuing a very awkward relationship. Or it's happened to you and you are left wondering what the heck just happened.
One of the main things that happened is that the relationship was never fully defined and the expectations were never set. This isn't something that we ever do. We get job descriptions but we never get relationship descriptions. It seems silly to think of it this way. Should we need to do all of that? Can't we all just get along?
Not in a healthy way until we are verbal about what it is that we need from each other. We assume too much. We require and demand too much from usually one person. We give the title of "Best friend" and put requirements on that one person to be our all in all, all the time, every time. It's not fair. One person simply cannot supply every need of another. We fail again when we say that our spouse "completes me." they can't. It's not possible.
That's God's job.
God made me. He is the only one who knows me and knows what I need when I need it and how I need it. When I put my needs on another human I set them up to fail. It is not someone else's job to make me happy or supply all my needs. It's not possible or fair. The story could go on with a million scenarios and examples and explanations of why this or that happened.
The bottom line is God is the only one who can complete us. After all, He has the blueprint in His heart of each and every one of us. He is the beginning and the end. Noone or no thing should ever take this truth from our heart. Is it nice to have human relationships? Of course. But they should never give you your completeness.
That's God's job.