A question about the psychopath and marriage for devious reasons

Not that they don't marry for devious reasons no matter what and quickly, my question is this: Why do they risk abusing the woman they want something from (sex, money, home, etc)? Do they not think about potential consequences of their behavior? That she might actually leave if she's not treated well? Particularly if he illicited those close to him to help draw her in (parents, siblings, kids, friends. This confuses me. Wouldn't it be easier to keep the mask in place for as long as possible or can they not help themselves if the intent is to harm (use) her?