Idun was not in love with Bragi. Maybe she believed that was case, but she was wrong. She had to be wrong. Because if she was right then she was in for a world of heartache that he wouldn't wish upon his worst enemy. He'd been there. He was there. Mostly, anyway. He didn't love Sif, but he cared for her a great deal. He wish to spend every waking hour in her company through all paths life would take them. He remembered each time they laughed, each time they fought, every time she cried. Loki would give a King's ransom to have her in his arms every night and fall asleep in a perfect tangle of limbs. But he couldn't have that. She belonged to someone else.
Not just any someone else either. To Thor. It caused Laufey's son far more heartache than he knew how to bear. Some days, it drove him to the brink of madness. There were still broken bits of glass and pottery in the kitchen, the entryway, the main hall and... well in nearly every room of his Hall... all of it left over from things he'd shattered in blind heartbroken rage.
He would spare Idun this pain if he could. But what could he do about it? She was surrogate family. She was the little sister he never had. His family consisted of a mother in Muspell, a father in Muspell that he never spoke to, a brother he spoke to about as frequently as he did Farbauti, an ex-wife and two daughters also in Muspell, a current wife that he mostly despised and he avoided at all costs in Jotunheim but had a child on the way and a brother by blood-oath who deemed to keep and discard him as it suited his immediate needs.
All he really had was Idun. At least reliably and nearby. What would he have done if had a blood-relation going through the same troubles? What should he do? What if it happened to one of his daughters? No matter how rare his visits to see Eisa and Einmyria were he would still defend them to the death. “I,” he started, not sure what to say. Was he supposed to challenge Bragi? Knock some sense into him? That wasn't really Loki's style.
Loki sighed. “It's poison, isn't it? Knowing there is nothing you can do to change their mind. It just sort of sits in your stomach and kills you from the inside out. It's toxic. You lay awake at night on the brink of madness wondering if there was anything you could have said or done... or could currently say or do, to change things. All the while knowing you were damned from the start.” He sighed again and brought his face to his hands. Loki could have easily have been talking about himself in that moment.
“And you go out, you put on a good face and smile and laugh and pretend that nothing is wrong when the one thing you want to do, more than anything, is smash everything in sight to bits out of complete and utter frustration.” He sighed again. “But you can't. So you try to move on. And you'll think you have, until you see them again and everything floods back in your memories and the pain starts all over again. Then you are back at square one.”
He looked up at her suddenly. “You have to confront him, Idun. Before this gets completely out of hand. I don't want you to wind up punching walls. Your hands are too small and delicate for that, you'll break your fingers and then who would make me pie and liquor me up while talking utter nonsense?”