There's no point in denying it any longer, Tomura has fallen in love with you, but he has no idea how to express it. Since you joined his army you have always supported him and treated him with kindness and so he has become emotionally attached to you, the problem is that he has no idea how to express it. He tries to make himself understood in his own way with gestures of protection and often possessiveness, but he sees that it doesn't bear fruit so he searched the web for what to do. You are not aware of his love and so you are having difficulty understanding his bizarre behavior