LILY FIXES A MISTAKE

Summary: Lily finds out James is cheating and decides to fix the problem her way.

Disclaimer: I don't own Harry Potter or any of JK Rowling's characters – Just playing with them.

Chapter 1

Lily stormed into Gringotts, a sleepy Harry on one hip. Gringotts was always open, so it didn't really matter that it was midnight. The goblins glanced up at her, eyes sliding immediately to her bruised face, then looked away, apparently embarrassed for her. Lily gritted her teeth, James would pay for her humiliation – he had crossed several lines, tonight - none of which she could forgive, and she intended to ensure he never had the chance to hurt her again.

*Flashback*

"For Merlin's sake, Lily I'm just going out with Sirius and some of the guys – you know we always go out on Friday nights." James ranted as he left the dining room.

Lily fumed, he had raced through the meal she had carefully prepared all day – she doubted he could have told her what he had eaten. She had been looking forward to her 6-month leave from work to spend time with a new baby. She hadn't expected to feel so lonely – and James kept staying late at work because of the increase in Death Eater attacks, and "going out with the boys" many evenings. She hadn't been out of the house except to buy food, since before Harry was born.

"Sirius has been seeing that stripper for months; you know that since its Basil Diggory's birthday he'll insist on dragging the whole lot of you there!" Lily's breath hitched – it was harder than she thought to get her pre-baby figure back, it was tough knowing that she would look rather saggy next to the stripper's bodies.

"Come on, Lily, don't you trust me?" James whined, batting the brown puppy eyes at her. He thought it was just as well she didn't know he had gone to the club several times over the last few months with Sirius. Harry was only two months old and they hadn't had sex since before Harry had been born. Lily was working on getting the figure back – he had told her to take the available potions for it – but she insisted on breast-feeding Harry, and so she couldn't. So he had to put up with a dumpy wife for several more months, he thought grumpily.

The sight of all those sleek bodies had been enticing and he had relieved some sexual tension with a very enthusiastic brunette several times, after all Lily hadn't been up to it, so why should she mind? As soon as Lily was back up to snuff, he would stop seeing the stripper. Sirius thought it a sound plan that was considerate to Lily. A little voice that he had been ignoring for weeks screamed that Lily would not agree.

Lily ground her teeth and answered, "Of course I trust you James, but it would be nice to see you for more than a few minutes at a time, as well."

Sensing victory, James smiled and kissed her cheek, "We'll go out for a picnic, tomorrow." He reassured her absently.

"It's October, James." Lily snarled, but he was already out the door, but not before she had cast a monitoring charm on him. She felt ashamed for that impulsive decision, but didn't end it.

Later that evening, sitting in a chair by Harry's crib, her heart had slowly crumbled as she watched the fawning girls – obviously very familiar to James, her heart broke completely listening to a brunette reminiscing to James about prior liaisons, and tears flowed as he followed her to a back room that held a small bed, and closed the door.

She was relieved to feel her temper kick in, it felt good to take control – it also numbed some of the pain.

She barked at the house elf to watch Harry, and to pack all her and Harry's belongings and be very quick about it; Then she apparated directly into the room with James and the girl.

Lily was never quite sure exactly what she had screamed at James, but he had leaped up, struggling to adjust his clothing. He had started babbling excuses, red-faced, just as Sirius had stumbled in looking guilty and confused. She did remember saying she had made the wrong choice when she had picked her husband, it was then that James had struck her in the face.

They had all frozen for a timeless moment, James staring in disbelief at his upraised fist, Sirius and his blonde gaping in horror, and the brunette smirking in triumph.

Lily simply apparated away – the lot of them weren't even worth a hex. She quickly grabbed Harry, shrank and pocketed the boxes and apparated to Diagon Alley. Her fury continued to climb, and she had several plans already cooking in her mind.

And, so, Lily found herself at Gringotts on a chilly October night, planning revenge.

A/N: I don't read a lot of marauders era stories, I hope I haven't copied anyone's idea – let me know if this is too similar to another story.