Ranking Every Couple On Buffy The Vampire Slayer
Like Angel, Spike has done many terrible things in his life and some of them to Buffy herself. Frankly, Buffy's relationships with Angel and Spike are both pretty toxic. But Spike is at least significantly more interesting than the broody, humorless Angel. Also, Spike is funny. Although, we can't (and won't) forgive Spike for sexually assaulting Buffy in Season 6.
Prior to the start of his sexual relationship with Buffy, Spike is steadfastly a villain in the series. Riding around town with Drusilla, generally causing mayhem wherever he goes, Spike's initial main goal is to kill Buffy, so he can continue his favorite sport of killing slayers. But Spike eventually discovers that he doesn't want to kill Buffy anymore, since he's developed feelings for her. They embark on a secret affair together and after the aforementioned attempted-rape scene, he decides he needed to make amends and prove himself to Buffy. So, he goes through a harrowing ritual to regain his soul. He then sacrifices himself to save the world in the series finale (though he's not gone forever, because he returns in "Angel"), thus further sealing his redemption arc.
Whether or not Spike's actions in the last season of the show make up for his previous behavior is hard to say, but his relationship with Buffy does provide an interesting arc for each character. Both Buffy and Spike grow as people during their time together. While none of Buffy's relationships could be described as "good" or "healthy," at least Buffy is able to find someone who she feels could be her equal.
If you or anyone you know has been a victim of sexual assault, help is available. Visit the Rape, Abuse & Incest National Network website or contact RAINN's National Helpline at 1-800-656-HOPE (4673).