A selfish coward. He may have not always known that he didn't want kids, but he was afraid to be truthful when he did know - and then he thought that his problem was solved by the infertility.

Basically his fear was that she cared more about imaginary children than her real live husband *and he was right.* I'm not saying he was behaving correctly here, since he's literally stolen years of her fertility with his lies. But I also know as a person who never felt the longing for children that her very real pain is hard to understand and he may have no concept of his cruelty.