Ladies
Spike & his motherOnly in the seventh season we learn about Spike's or William's relationship with his mother. We learn that he loved his mother very much. He used to read her his bloody awful poems and she seemed to be the only person who liked them. It was about the same time when his mother got sick and William was bitten and turned by Drusilla. To give her the possibility of eternal life - with him - he made her a vampire, too.
As soon as she was a creature of the night she started to insult her son. She hurt William so much that he finally staked her.
Spike & CecilyA long time ago, before Spike became a vampire and when he was still the bloody poet William he was in love with a young lady called Cecily. When he opened his heart,
she started laughing and said he was 'beneath her'. He ran off, frustrated and sad, when Drusilla found him and turned him into a vampire.
Spike & DruThey were the big couple in Season 2 (sorry, I forgot Buffy & Angel :-) They were together since Drusilla turned Spike into a vampire in 1880. When she became ill he cared for her. He did everything for her. After Spike had worked together with Buffy to save the world, Dru left him,'cause he'd gone 'soft'. He tried everything to get her back, but he failed.
In Season 5 Dru comes back to Sunnydale and learns about Spike's chip and that he loves the slayer. When he tries to kill her for Buffy, she leaves again.
Spike & HarmonyDuring Graduation Day Harmony, Cordelia's friend, was turned by a vampire. In Season 4 she's back - as Spike's girlfriend.Obviously this relationship doesn't mean very much to him. He always shouts at her and lets her know that she's driving him crazy. When he gets his chip she leaves him to start her own gang and kill the Slayer herself.
Spike & Buffyclick here to read the whole storySpike & AnyaAfter both of them had been dumbed by their lovers they spent some comfy time at the Magicbox alone. The whole evening develops into a one night stand and everyone is watching. That night ends the Xander/Anya relationship leaving both in anger. Also Buffy is angry, she never wanted anyone to find out about her and Spike.
Spike & FredWithout spreading any rumours, but there is a slight spark of chemistry between the two. And still, Spike's 'life' depends on Fred.