Ran Haitini ⁹

"I'm just asking, Sakura was cold a moment ago and you gave her your jacket. I'm cold too, Ran, in fact, I'm shivering, and I'm your girlfriend. Why don't you ever... why don't you ever do those things for me?" To my surprise, instead of calming down or trying to understand, Ran's reaction was explosive. Her jaw tightened and she took a step toward me, looking at me with a contempt that hurt more than the icy wind.
"Are you serious? You're jealous of your own best friend? How low you've sunk," she said with a grimace of disgust, shaking her head in disbelief. "You're incredibly selfish."
"I'm not jealous, I'm just asking for a little reciprocity!" I replied, my voice breaking completely. "I'm your girlfriend, Ran! I'm supposed to..."
"She's more fragile than you!" he interrupted, raising his voice suddenly, losing what little patience he had left. "Sakura is delicate, she needs to be cared for. Are you blind? You, on the other hand, always act tough, you endure everything, you're stubborn and obstinate. She deserves to be better cared for because she doesn't have that unbearable shell you wear all the time."
I froze; her words hit me like buckets of ice water. Was being strong, enduring, and not complaining now a punishment? Did not being a damsel in distress mean I deserved to be ignored in my own relationship?
—A suit of armor? — I whispered, feeling a traitorous tear roll down my cheek —I'm asking for love, Ran, I didn't ask to be invulnerable.
"There you go again," he huffed, rolling his eyes in exasperation and turning to walk over to Sakura, who was looking at him with a mock-compassionate expression as she touched his arm in support. "You're embarrassing when you get this possessive and envious. You should be ashamed of yourself for treating Saku like this, all she does is hang out with us. You're a terrible friend and an unbearable girlfriend."
Sakura gave him a sympathetic look and whispered something in his ear as they walked a few steps away together, leaving me standing there.

Ran has a certain favoritism towards your best friend Sakura (who is a pick me), even though you are his girlfriend. For him, it's fine to be attentive to her, and he thinks you are just selfish for not wanting him to treat her well.