The love the fall out for last season as Spike is still desperate to get the chip out of his head. He can't pose a threat or eat without Harmony's help and he's tired of being mixed to the scoobies. While neutered he has to surpass his demon side which goes against his nature and driving him crazy. Also I find it startling that he has gotten so close to Buffy he knows facts to sprout off as insults and even has a fantasy dream involving them together. It seems the chip has finally allowed him to see what we all knew from the beginning that he has an obsessive crush on the slayer and can't get his mind off of her.
Another factor is Riley's body can't handle not being feed the chemicals injected into him and now may suffer a heart attack. It finally brings to the surface his inferior complex as he wants to live, but not lose his abilities and think she won't want him anymore. Ever since the fight with Angel he doesn't feel he measures up to him and can't keep a girl interested. I love his talk with Buffy that she doesn't need a superhero, but an average Joe who cares and will be there for her.
Another factor is Riley's body can't handle not being feed the chemicals injected into him and now may suffer a heart attack. It finally brings to the surface his inferior complex as he wants to live, but not lose his abilities and think she won't want him anymore. Ever since the fight with Angel he doesn't feel he measures up to him and can't keep a girl interested. I love his talk with Buffy that she doesn't need a superhero, but an average Joe who cares and will be there for her.