Missing scene from HBP, detailing the real problem with Remus and Tonks.
And she grabbed his arm and dragged him into the corridor outside. He chose the say nothing, and do nothing, though his passivity did result in Tonks having the drag harder; she was past letting this intimidate her. When she let go of his arm, he looked in the general direction of his feet and said, "While we are here, I would ask that you spend some time with Minerva later tonight. This is a harder night for her than you could have realized-"
Of all the things he could have said. Tonks exploded. "Actually, I can realize exactly how hard a night this is for her, you hypocrite! I thought you might have supported her and Albus. You both knew about them, didn't you, and they knew about you, confirmed on all sides I'll bet! He wasn't too old for her!"
"Tonks, I'm more complicated than just that."
"And Albus Dumbledore wasn't? He did the same thing you're doing, did you know that? I went to her from advice-don't laugh, I felt I could trust her to keep silent, that's why-and she told me the whole story, and maybe we'll tell you someday but that doesn't matter. I'm sure you know how it's all done, because if you didn't do the whole song and dance with Sirius too, I'm going to be really angry with you."
"Did Minerva tell you about that too?" Remus inquired. "It didn't seem to discourage you any."
"I figured if you were one hundred percent gay, no chance for any woman, you would have told me that long ago. And no, she didn't breath a word of it, how could you even think she would? Not even a mention of the name of Sirius from her. I've come to it from my own observations, just like half of the Order. Okay, I haven't been sure, in fact, I've spent the last two years trying to decide whether I thought you were or not, and do you know, you are so damn stoic, you nearly convinced me you weren't for the longest time. I know sub rosa affairs seem to be the custom around here, but dammit Remus, you are so bloody closed up a dozen enchanted crowbars couldn't pry you open!"
"That," he said coldly, "is my business. And as for my relationship with Sirius Black, he had managed to convince me already, through more years than you've even known me, that he was willing to hazard life and limb, and give up a very great deal for me. He knew exactly what he was getting into. You don't."
This did not please Tonks at all. "So I'm just a little girl who doesn't know what I'm getting into, is that it? Never mind that I'm an Auror, never mind that I've fought alongside you..."
"Tonks, I didn't mean that," Remus tried.
It didn't work. "Yes you did, or you're a double hypocrite! Hell, you're a double hypocrite anyway!"
Her words were having an effect. Remus was looking ashamed, despite his attempts to hide it by keeping his head down.
"Sirius would have wanted this for you," she said, more gently. "He wouldn't have wanted you to curl up and die, I'm sure of it. That's really it, isn't it, whatever else you say? You can't let him go, whether you admit that to yourself or not."
Remus's head was now at a right angle with his shoulders, but Tonks thought she saw a tear in the corner of his eye.
"When you're ready to let your heart live again," she said, "you know where to find me." She kissed the top of his head, added, "Of course I'll look in on Minerva some time after she's done with the school's business. Make sure you do too," and turned and walked away, and suddenly felt very light, as if the heavy burden that had been on her shoulders since the previous July, since she'd first realized she was in love with Remus, had lifted. She wasn't going to try just at that moment, but she thought it possible that if she attempted to make her hair pink again, it just might transform.