Paige was in a relationship with Emily at one point. Before that? She pushed Emily's head underwater when her obsession with being the better swimmer took over. Yikes. It makes sense then that fans hated the character.
Emily and Alison's relationship was not built on strong foundations. They ended Pretty Little Liars together, but it was revealed on spinoff PLL: The Perfectionists that they were getting divorced. They weren't great together.