Your ideals in life conflict, and you aren't both able to express your own at the same time that your lover is asserting theirs. You are naturally much more accepting of ideas that involve speculation and intuition, and you have a hard time explaining them to your lover, who insists on proper proof. When you can't give it -- after all, who can prove the intangible, like love or hope or faith?
-- you may start doubting yourself and your beliefs. On the other end of that dynamic is your lover, who thinks they have a very good reason for challenging your ideals -- in their mind, your ideas are baseless. They seem to your lover as if they have no foundation in anything that can be properly trusted, much less understood, and that to them translates as worthlessness. Their ideals have been developed through careful weighing of the alternatives and consideration of all angles, so they tend to distrust anything that involves 'gut reactions' or anything else that's hard to put their finger on. But their perspective denies an entire facet of human experience. You two have a hard time communicating the importance of your own point of view, because you aren't able to respect each other's. You may feel invisible in this relationship, if you don't do something to grab your partner's attention.