Buffy & Angel
Spike & Drusilla
Buffy fell for Angel only to discover he is a vampire. The relationship lasted for nearly three years, but in the end Angel broke up with Buffy and left town so she could move on with her life since they couldn't be togther.
Drusill sired Spike and the two remained together for over a hundred years, but Drusilla broke up with him when she realized Spike was obsessed with Buffy. The two got back together, but the relationship soon ended when Dru realized Buffy was still in Spike's head.
Buffy & Riley
Spike & Harmony
Buffy and Riley got together, side by side they faught demons and vampires, but it was soon obvious tto Riley that Buffy didn't love him. Riley started cheating on Buffy and she found out. Riley planned to leave town, at the last minute Buffy went after him, but it was too late, Riley had left town, paving the way for the best couple yet...
Spike didn't really love Harmony, in fact he didn't really even like her. He was on the rebound from Drusilla. They had an on again- off again relationship, but in the end Harmony left Spike realizing he would never love her, paving the way for the best couple yet...
Buffy & Spike
Buffy and Spike were mortal enemis, it was almost two years after they had met that Spike relized that his obsession with killing Buffy was turning into something more, he was beginning to have feelings for her. At first, Buffy was disgusted by Spike's feelings for her and rejected him. But in time, she began to develope feelings for him herself. The two went through a love/hate relationship, it wasn't until after they broke up that they began to become real friends and their feelings for one another deepened.