It's been three months, and he can't push away the shuddering fear that it isn't her. After all, he made that mistake before, so easily, so willingly.
It was a constant, nagging fear at first, gnawing at him to the point that he didn't want to let her out of his sight. Now it just catches him unawares every few days. He still doesn't want to let her out of his sight, but he forces himself to not let it show. Even though her bruising disappointment has waned, he wants more than anything to never hurt her again.
He wants more than anything to stop fearing her and doubting himself.
He just wants to be sure of something again.
~~~~~
They're in the lab, the old one at Harvard that's still full of equipment, fetching something for Walter. The light catches her eyes just right, and he's convinced, absolutely, that it isn't her. Between one breath and the next, he's trembling. Her voice is low when she notices, concerned, and he doesn't mean to, but he flinches away from her.
He hates that he's like this, like he's the one who was wronged. He hates that she's the one holding him together after everything he did.
He searches her face for something, something, anything that could reassure him.
She doesn't try, doesn't say anything, just stands near him until his heart stops pounding and the adrenaline clears his system. His hand is shaking when he rubs at the stubble on his chin and mutters apologies.
She doesn't say anything to that, either. It just makes things worse, because both of them know very well that it's not okay and forgiveness doesn't really change anything. She just holds his hand until they leave the building, and her warm presence eases the shaky, hollow feeling that the panic leaves in its wake.
~~~~~
They're having breakfast a few days later. Astrid and Walter are talking about cartoons, and Olivia is jotting notes on the case file she has open on the table next to her bowl of granola. She glances up at Peter and watches him for a while. When Astrid takes Walter to get more waffles from the cafeteria line, Olivia draws a little X on her wrist, then pulls her sleeve down over it.
Peter catches a glimpse of it that afternoon, when they're leaning over a tank filled with giant leeches, and he smiles.
~~~~~
It's not always X's, and it's not always her wrist. It's not even always her that does it. The first time she offered him the pen, he pushed up the sleeve of her shirt and scrawled his name on her forearm. That earned him a glare, but she did let him help wash it off later.
~~~~~
He's amazed how much it helps. The sight of smudged ink on her pale skin holds off the panic better than anything she could possibly say to him. It still happens, and sometimes he has to fight the desperate urge to claw at her clothing to see it, but she's good at reading him. She gets them alone and lets him stare at her skin until he's as sure as he can be. He rubs his thumb over it, and the motion mixes the smell of the ink with the smell of her skin, and Peter thinks that maybe, someday, he'll stop being afraid.