Lily knew that when Sirius had told her he was going to watch the Gryffindor quidditch team practice, he was lying.
She had seen the looks he and Annette Parker had shared when they had thought no one was looking. Looks of forbidden desire and secrecy passed ever more frequently than before, as if their 'relationship' had been taken to the next level. Which level that was Lily had no idea.
She was not stupid and knew that something was going on between them. Sirius was supposed to be her boyfriend; he was supposed to share those looks with her, not with another girl. Lily knew that every time Sirius lied about going somewhere he was off to see her.
Lily could not see what Annette had the she hadn't. They had the same sized frame, around the same breast size; everything was practically the same apart from their hair and eye colour. When it came to their personalities however, Annette was cold and snobbish. She had friends, bet whenever one said or did something she did not like she would bitch about them for days.
Lily did not want to believe that Sirius could betray her like that, but she could not ignore the evidence. Next time she would follow him under the disillusionment charm to find out the truth. Even if it broke her heart.
