They'd either understand and help you, God forbid, or drive you out where you could finally be at peace, in the dark, with me.
Does that really sound like someone who wants Buffy to tell her friends so she can be "in the light" again, so to speak?
"They'd either understand and help you,
God forbid..." Doesn't sound like he WANTS Buffy to get this "help", does he? It actually sounds very much like he wants her "in the dark, with him." Maybe as a vampire, he just can't see that for a human to be "in the dark" is a bad thing. All along, Buffy believes that Spike is infatuated with her because he likes pain, he likes misery, and he's hardly disagreed because he is a vampire, after all...and maybe he honestly believes that it's normal, and that for Buffy to seek out the same things is okay...but I don't know if I buy that. He didn't fall in love with depressed, misery-seeking Buffy. He can't be so blind that he doesn't see what being with him is doing to her.
I agree that the fact that Buffy was having sex with a soulless vampire was upsetting her. But I disagree that's why she claimed "It's killing me." Her confession to Tara in "Dead Things" is extremely telling.
Buffy: This can't be me. Why do I feel like this? Why do I let Spike do those things to me?
Tara: You mean...hit you? (pause) Oh. Oh...really.
Buffy: He's everything I hate. He's everything I'm supposed to be against. But the only time that I ever feel anything is when...Don't tell anyone, please.
Tara: I won't.
....
Buffy: Why can't I stop? Why do I keep letting him in?
Tara: Do you love him? (pause) It's okay if you do. He's done a lot of good, and he does love you. And Buffy, it's okay if you don't. You're going through a really hard time, and you're...
Buffy: What? Using him? What's okay about that?
Tara: It's not that simple.
Buffy: It is. It's wrong. I'm wrong. Tell me that I'm wrong. Please. Please, don't forgive me, please.
Now, I know people will read into this scene (and, in fact, this episode) as they like. But when I watch that confession, here's what I see...when Tara asks if Buffy loves him, she looks away. She's ashamed that despite the good he's done, and the fact that he loves her, she's only using him. When Tara says it's okay if she doesn't love him, she looks up again, more upset than ever. In Buffy's opinion, it's NOT okay to use Spike. It's wrong.
It's making her wrong, and bad, and evil. It's killing her.
Since I'm talking about this episode, I might as well mention what happens earlier, when Buffy beats up Spike. I think we can all agree that when she's beating him up, she's actually beating up the part of herself--the depressed part that she can't understand. She starts by attacking the soulless Spike in front of her; he's decked out in vamp face and everything. And she stops when he's back to his human face, when he's swollen and bloody, and she looks appalled that she inflicted that much damage on him. Not on a soulless vampire. But on Spike. Someone who cares about her very much.
Notice when she breaks up with him, she breaks up with "William." Not the soulless vampire. But William, the sensitive,
human, kind and intelligent poet. To me, her guilt has little to do with Spike's not having a soul...although that aspect certainly confuses her. (How often did she defend her relationship with Angel by explaining that he had a soul? I think the fact that Buffy, a Slayer, can have relations with a vampire at all causes her a lot of turmoil, but that's probably best for a different thread.) To me, her guilt has much more to do with the fact that she's using someone who loves her.
Anyway, this was longer than I intended it to be.
I do believe the relationship with Spike, S6, was killing her. And yes, she initiated a lot of it, and yes, she was using him. But IMO, he was not helping her. Emotionally, before the relationship turned physical, he helped. He was there for her, she shared secrets with him, etc. I think, had the relationship stayed that way, he could have helped...he could have become a trusted friend and ally sooner than what he became S7. But by bringing a romantic aspect to it, I feel like everything snowballed for her. She kept feeling worse and worse. So did Spike. And I guess I just sympathize more with Buffy.