Life has been in colour for MJ since she met Peter in high school. She wouldn't lie, it was exhilarating to see in colour. Life was just better in colour.
Peter introduced MJ to Pepper when they were 16, and almost immediately after, Pepper asked MJ to be her personal assistant. Now, MJ was halfway through her working hours. She was 20, and Peter just turned 21. She was on her break when things started loosing their vibrancy, slowly. She launched out of her seat and dashed to the elevator. "Med Bay Fri!" She exclaimed as the door opened. Once at the Medical Wing, she saw Bruce and Tony.
  "MJ, take a seat, you need to breathe." Bruce coaxed, but she refused.
  "He-he's dying. Peter's in trouble." She stumbled. She never stumbled over her words. She was 'BadB MJ'. She was all strong and brave, even when her idiot boyfriend wasn't. Bruce sat her down in a chair as Tony suited up, but she didn't notice, all she thought was 'nonononono'.

By the time Peter, the love of her life, was in the Medical Wing, only his suit, and the blood draining from it, had colour. He had time. Maybe not much, but he still had it. Then Bruce pushed her out, told her to try and focus on something else. So she did. MJ called the elevator, and made her way to Peter's lab, using the once blue holograms to create a suit.

She'd sent the finished product to print, mildly aware that it was 3, meaning she'd worked through the night and into the afternoon of the next day, when the holograms she'd stared at for far too long grew into a noticeable blue hue.

When her Black and Blue coloured suit was, finally, finished, the entire lab was in colour. MJ suited up, and rushed to the window, opening it, and jumping out, thrusters on. Her calculations were, thankfully, correct, and she flew to the Med Bay, crashing through the window. Tony raised his blaster, and so nearly shot her, but she rushed to Peter's side faster than she thought.
"MJ..?" He rasped.
"Hey, Loser." She removed the mask to her suit, to reveal her tear-soaked face. "You *never* get to do that to me again, okay?" She demanded an answer.
"I can't promise-"
"Yes you can. Karen'll tell me every time you so much as get a *scratch*." Bruce and Tony were confused. "My god, you're stupid! You nearly died!"
"But didn't! I'm fine! I heal! I'll always get back up!" Peter explained, glad he was alive, and glad his girlfriend was okay, but he wouldn't let her get hurt. Not if she was trying to help him. He was Spider-Man! His job was to keep her safe.
"What if you didn't? What would I do? If you were out saving the world, and then I lost mine?" She pushed. "I'll never stop you from doing what you love, but I want to be there, to make sure you're okay while you're doing it."
"... Cool suit?"

Just a short one I wrote without internet

Incase it wasn't obvious, in this AU, when you meet your Soulmate, you see in colour. If your Soulmate dies, no more colour. Basically, Peter was bleeding out, so MJ couldn't see much colour.