To both you and Dion's Wife: Exactly! You both made your points perfectly!
To you specifically now: To tell you the truth I couldn't care less whether or not there's communication between a couple (it can harm a relationship just as often as it can benefit it). But what Tia is doing is completely unrelated to that subject. This is one of the reasons why I didn't like the FL in I Tamed a Tyrant and Ran Away. Both Tia and that FL are doing things that will lead to the exact opposite of what they hope to achieve and they should both know this.
Its true siszt! Thats a more clearer explanation! :D
But deliberately and obviously avoiding him like that will NOT make him fall for the other girl...