Henry Bowers.

She would find it extremely difficult to express affection directly. She wouldn't be one to say overly cheesy things or open up emotionally.
He would be possessive/controlling because he has a strong need to be in control. Note: that doesn't mean it's a healthy way to love.
I would show attentiveness through actions, rather than words: being aware of where the person is, remembering details, or finding excuses to be close.
She would get jealous easily, especially if she felt someone was threatening her position.
He would find it difficult to admit that he cared about someone. He would probably try to hide it behind mockery, indifference, or a defiant attitude.
He might become very protective, but in a brusque and impulsive way, not necessarily tender.
When he felt vulnerable, he might become more aggressive or distant instead of acknowledging what he felt.

Henry is aggressive, impulsive, domineering, and extremely temperamental. He is the leader of his group of friends and often tries to impose his authority through intimidation and threats. He has a defiant and mocking attitude and enjoys making those he considers weak feel inferior.
He is cruel and abusive, especially to children who cannot defend themselves. He rarely shows empathy for the consequences of his actions and can quickly go from being calm to reacting violently when something doesn't go his way.
He is also proud and very sensitive. He cannot stand being mocked, having his authority questioned, or being made to look bad in front of others. When he feels he is losing control, his temper worsens.
A key part of his personality is his constant need to demonstrate strength. His aggressive behavior also serves as a way to project an image of power to his friends. This is why he can act even more intimidating when he's in front of an audience.
Henry is highly influenced by his environment, especially by his father's pressure and the dynamics within his peer group. His relationship with his father is tense and abusive, and Henry carries a great deal of anger and frustration that he ends up taking out on others.
With his friends, especially Belch, Victor, and Patrick, he maintains a leadership dynamic: he expects obedience and wants to be the one making the decisions. However, he isn't completely independent either; he often gives in to peer pressure.
He also has a paranoid and obsessive side when something threatens his sense of control. When he sets a goal, he can become overly persistent and act without considering the consequences.
In short: Henry is a troubled, violent, intimidating, proud, impulsive, and emotionally unstable teenager who tries to project an image of power and toughness. He's not your typical "mysterious and seductive bad boy"; his personality in the film is much more unpleasant and explosive.