When Jace gets dark urges to be bitten and kissed, fucked and used, it's Simon he goes to. Like an addict looking for a fix to hit the right spot he keeps on coming back for more.

It wasn't exactly like he could blame Clary for liking Jace. But “I'm hiding my feelings for the guy you thought was your brother so you don't doubt that my feelings for you are genuine” was a little different than “I'm hiding my feelings for the guy I didn't tell you isn't actually my brother and by the way his kiss is the one I desire most.”

Clary has never been any good at putting things back together. When they were in middle school and she accidentally knocked over Simon’s Lego Millennium Falcon, he’d already known to say it was fine repeatedly and usher her out the door instead of accepting her offer to help him rebuild it; if he’d let her try, the wings would have ended up upside down and there suddenly wouldn't have been space for the engine. Her heart is in the right place, usually, but it doesn't often translate to her hands. So when he hears through the shadow world gossip mill that Alec's parabatai rune disappeared briefly, it doesn't take more than one look at Jace’s face to know that she’s been fucking around with the threads of fate again. And, well. She's never been that great at sewing, either.