Should is a strong word. The world is what it is. But I tell you from experience. It will hurt a lot less to handle romantic relationships as transactional. Save unconditional love to children.
Psychology textbooks point that out as a Maladaptive Coping Mechanism.
Not trying to mock you or be oppositional - I would invite you to check it out, but the Wikipedia article is not detailed enough.
- Someone with a proper background in psychology wants to weigh in?
None offense taken, but what is "that" that it points to?