This doesn't really track. I doesn't follow that if you can not live together there must be something "wrong".
I will not live with my partner for a number of reasons. First of all, I'm a neat and tidy, everything in it's place type of person. I can be tyrannical about the state of my living space when other people upset it, this causes me distress, so it's preferable for me to live alone.
My partner has ADHD, their living space is chaotic, they are disorganised, messy, and struggle to keep on top of some aspects of domestic life in a way that is totally alien to my lifestyle. There is no way I'd want a person like this sharing my living space, and although I still go to their home, I don't spend a lot of time there because I'm never properly comfortable.
So there is nothing "wrong" with our relationship because we don't live together, it's if you did put us in the same living space that out relationship would go "wrong" in short order, hence why we can not live together rather than just do not live together, and why neither of us has any intention of ignoring reality and pushing the issue anyway.
I also agree with PP that living with your partner is a guaranteed way to kill romance, spontaneity, affection, and breed simmering resentment over otherwise trivial and minor issues. I've experienced this first-hand and have no intention of ever putting myself in that position again.