Separating the money question from the field question

Most parental disagreements that look like one argument are actually two. One is about what the household can or should spend. The other is about what the child should study. They get fused together, and then neither gets resolved, because every discussion of the subject is really a discussion about money and neither of you has said so.

Split them deliberately. Agree the number first, on its own terms, without reference to which course it might pay for. Then discuss the field as a separate conversation on a separate day. Most couples find they agree on one of the two far more than they thought they did.