We need a lot more stories about Spike getting rid of the soul. This challenge is a way to see if I can jumpstart anyone's muse. The symbolic value of Spike getting rid of the soul with the help of Buffy is beyond measurement, so I would love to see many more stories about that. The important thing us that he get rid of it forever. This is one possible scenario. The name could be something else.

This needs to happen some time after season 7 because it need some time to develop. 

Spike and Buffy are having a relationship and one time when they are talking Spike mention how he didn't really love her before the soul how he was someone else then  and how she should kill him if he lost it.

This get Buffy thinking "This doesn't sound like Spike at all this is something Angel would say, what is happening to him?" This makes her do some research and find out that since the demon is taking the place of the soul in a vampire, getting the soul back is harming the vampire mind. Angel's idea of himself as a separate entity from Angelus is a form of insanity and now Spike is starting to show the same symptoms.

This naturally leads to one conclusion, they must free Spike from the soul. 

Naturally there has to be some angst in this. This goes against everything Buffy thought she knew and knowing her there should be some guilt involved. There's also a worry, "what happens after the soul, Angelus was insane after all". There's also the question, is it right to save someone from insanity when they think they are fine.

There are many possibilities for emotional struggle here and other characters can be involved in this. 

The story of course must have them getting rid of the soul. If Spike is somewhat insane afterwards he must be able to heal from it. Buffy and soulfree Spike must of course be together at the end of the story. The realisation that soulfree Spike is better for the relationship should be there. He is the one that could truly balance her. So a happy ending is a must.