Constantine was thrown out before lunchtime because he could not understand Aragorn and Arwen's love.
Although the concept of love often appeared in the literature and history he had read, and Salomon and the Witch had personally demonstrated what an emotional life was, the Praetorian Guard had no mental or physical need for women or love. Their loyalty to Salomon and their desire to fulfill their mission were the only emotions they possessed. Therefore, even though he could appreciate the beauty of the elves described in books and admire the artistry of the writing, Constantine could only understand Aragorn and Arwen's feelings in his own way, forcing that relationship into reality from an extremely rational perspective to help himself comprehend it.
That was, love between a human and an alien.
From a certain perspective, the elves in the book were quite compatible with human aesthetics in both appearance and spirit, so cross-species affection was not impossible. Constantine understood that perfectly. But as one of the people in charge of Secret Wars, Constantine had seen more than once in reports during the purge war against the Skrulls that some human women had accidentally discovered their husbands' true forms yet still insisted on pursuing a relationship with them, even going so far as to resist armed personnel. However, aside from a small number with particular fetishes, such as demanding that they transform into some female celebrity that day, this rarely happened with male and female Skrulls. At least, the sample data collected so far proved that this was the case.
This forced Constantine to marvel at humanity's genetic instinct to reproduce. He extended the discussion to the relationship between Neanderthals and Homo sapiens, then seriously discussed with Salomon why this behavioral pattern benefited species reproduction and could even allow early humans to