So I got sucked into r/buffy again over the weekend (I know I know) and the amount of misogyny disguised as performative feminism is killing me. As is the attempt to distill S6 into a "Spike bad/Buffy victim" when the actual story is so much more complicated, nuanced, and heartbreaking than that.
I will say I absolutely sympathize with Buffy 100% throughout S6, more than I do Spike. This is a big reversal of how I felt 20 years ago, but reflective of my own experience with self-hatred and depression. That said, I also 100% sympathize with Spike and recognize a few fundamentals that antis can't seem to grasp:
He's trying to be what Buffy needs
He can't be what Buffy needs, but he doesn't understand why
He doesn't have a soul, ergo he's incapable of meeting her at the level she needs. This is not a choice on Spike's part; it's simply fucking nature.
Death/darkness/disassociating from society is a GOOD THING in Spike's mind. He found the ultimate freedom once he rejected societal pressures and stopped trying to win the approval of his peers. He fully believes Buffy will be happier if she does the same.
Is it selfish? OF COURSE IT'S SELFISH. He can't not be selfish because of the no-soul thing. But that doesn't mean his motives are inherently bad; it means his understanding of the situation is fundamentally flawed.
In Spike's mind, Buffy seeing things Spike's way is what will set her free. This mentality is of course wrong and toxic, but his intention is not to break her down, rather cut the chains he sees holding her back. Being human did him no favors. He's trying to share his experience and becomes increasingly desperate as these attempts fail.
Throughout all of S6, with very few exceptions, Buffy pursues Spike. She does in OMWF, Tabula Rasa, initiates sex in Smashed, Gone, Doublemeat Palace, and in Dead Things, save the balcony scene. We also see that she WANTS Spike in her dream sequence, specifically in her bed the way a normal boyfriend would be.
Buffy's only source of comfort and support at a time when she needs it most is coming from someone she believes she should be ashamed of, and that is what hurts her more. She's expected to take care of Dawn, of Willow in the midst of her recovery, participate in a wedding, balance being the SOLE BREADWINNER in her home (for reasons that are never addressed, much less acknowledged), along with the intense trauma of having been ripped out of heaven and KNOWING that peace exists out there somewhere and she can't have it. That the only person who seems to see her struggle, understand her, and provide any reprieve is also someone she has been conditioned to believe she shouldn't like, much less love, compounds her intense self-loathing and her belief that she is wrong. She wants the answer to be that she came back wrong because being wrong means being released from the expectations and responsibilities of being Buffy Summers.
This is what Spike can't understand, and not because he's stupid or evil or selfish, but because by the show's own lore, he is incapable of understanding it. His best and only connection to the human world is broken; it's not Buffy's responsibility to be his compass, but she IS his compass. She's the reason he's changed as much as he has, how he models his behavior, the reason he has evolved, and she's emotionally incapable of being that for herself at the moment, much less him. Again, not a burden she should have to shoulder to begin with, but a result of the natural order as dictated by the show's lore. Spike's humanity is nurtured through his connection to Buffy, and his connection to Buffy changes from day to day as her internal processes change.
I don't think "mutually abusive" is the right term as we understand it outside of Buffyverse because that has a lot of real-world implications that are absent from this fictional paradigm. But setting aside those implications, the dynamic is MUTUAL and ABUSIVE. It is intellectually dishonest to apply human motivations and power dynamics on inhuman characters stripped of the very specific conditions that allowed those dynamics to become what they are. It's also appalling to claim that Buffy was Spike's victim when she was calling the shots throughout the bulk of their relationship; it completely strips Buffy of her agency. Women can be depressed. Women can make bad decisions. Women can flounder, struggle, and fail because of themselves and crack under the pressure others put them under without being someone's victim.
Also? Denying Buffy's abusive behavior to Spike is similarly appalling. Slayers are understood to be physically stronger than vampires, the same way as most men are understood to be physically stronger than women. If a man beat a woman bloody in an alley and abandoned her there, would you say she deserved it? Would it be acceptable if you knew she was asking for it? That the man had had a really bad day? That he was going through something and trying to work some stuff out?
Season 6 is complicated, especially the Spuffy dynamic, because these are two broken people trying to not be broken and unable to help each other the way they need. But they were broken people, and that fracture was mutual, regardless of how uncomfortable that is. It's also why Season 6 is one of the show's strongest seasons. It takes us to pretty awful places but also shows us the way out. Trying to minimize that or make it black-and-white is a lot of things, and none of them are good.