If two people, especially a man and a woman, are unsuited to each other, they have different personalities or interests, and so are unlikely to have a successful relationship. By the end of that first year, I knew how totally unsuited we were to each other. = incompatible suited
If someone or something is unsuited to a particular job, situation, or place, they do not have the right qualities or characteristics for it. He's totally unsuited to the job The snow cruiser proved hopelessly unsuited to Antarctic conditions. suited