So, I've noticed this ongoing argument on Reddit which goes as follows:
"Spuffy was toxic in season 6."
"Yes, but it was healthier in season 7 after he got a soul."
"No, it was codependent."
I think they base this on when Giles tells Buffy, "There's a connection. You rely on him, he relies on you. That's what's affecting your judgment," in the episode 'First Date.'
I decided to look up what exactly makes a codependent relationship and I have to say, that it could be argued that Buffy had codependent relationships with EVERYONE and they were quite happy for it to stay that way.
Let's break it down. A codependent relationship is where one person (the "caretaker") sacrifices their own needs and identity to fulfill the needs of another (the "taker"), who relies on this excessive support.
Buffy constantly does this, even to the point of sacrificing her own life and her friends just accept it. She's the Slayer, it's her duty, responsibility and identity. Buffy will save the day. Giles, especially, constantly reminds her of it.
The caretaker often neglects their own needs, desires, and identity, becoming defined by their role in serving the other person. Buffy is like this regardless of Spike because she is the Chosen One. She was like this long before season 7.
Difficulty setting boundaries is common, driven by a fear of disappointing others or causing conflict. Xander certainly doesn't respect her boundaries and Buffy always pushes herself because she doesn't want to disappoint (especially Giles.)
Buffy struggles to prioritize her own needs, or feels guilty for doing so. Especially when it comes to her choice of partners. Yet, she goes against her friend's disapproval in season 7 and says, openly, that she needs Spike.
She feels like she has to rescue or fix everyone's problems because she's the Slayer. She fears being alone or abandoned because of her father, Angel and Parker. She constantly forgives everyone and gives them second chances - not just Spike.
If anything, Spike reveals to Principal Wood in 'Lies My Parents Told Me' that he knows the mission and her duty as the Slayer will ALWAYS come first and he's okay with that. He has faith in her helping him, but doesn't take it for granted. He tells her to kill him when he's a danger and also offers to leave Sunnydale.
All I'm saying is, you can't blame Spike for Buffy's tendancy to be codependent. That started back in season 1 with her relationships with Giles and the Scoobies.