Hey DaniellaWidget,
The first one could be Touch of Jealousy by Echidna
TSR EF Nocturnal Light
part1 part 2Summary: When B&S discover that their respective counter parts(Dru&Angel)have been macking on each other they're heartbroken & decide 2 get them back by making them jealous.The plan?Pretending to be an item, problem is that every1 knows they HATE eachother!
The second one could be
His Dirty Little Secret by jamesgirl
Summary: William 'Spike' Giles and Buffy Summers are both students at Sunnydale High, but they lead two very different lives. Spike has it all – looks, wealth and popularity. Buffy has nothing – since her parents divorced, she's been living in the servants' quarters of the Giles mansion, where her mother earns a meager living as a maid. But beyond these differences, they have a secret relationship – at school, Spike pretends not to know her, but at night he visits her room with growing regularity...
Hope these are the ones you're looking for.