"BUFFY IMMEDIATELY TAKES DAWN FOR SPIKE TO WATCH OVER. DO YOU THINK SHE’D LEAVE DAWN WITH A “RAPIST”? WHEN SHE FINDS CLEM INSTEAD, HE TELLS HER SPIKE LEFT, BUFFY ASKS WHY AND LOOKS WELL BEYOND A LITTLE SAD AS WELL, Y’KNOW WHILE SHE TRIED TO DITCH HER SIS ON “THE RAPIST”…."
In Beneath You, Buffy explicitly states that Spike tried to rape her. She explicitly states he failed because she stopped him. Rationally, we would think that a victim of violence would not continue to trust the person who hurt them, and would not have affectionate feelings for them. But in reality, victims don't always act rationally. A victims having positive feelings towards a person who abused is not evidence that the abuse didn't happen. A victim wanting a person who abused them to stay in their life is not evidence that abuse didn't happen. People are complicated, and these situations are usually more complicated that we give them credit for.