The problem, thinks Balthazar, with loving someone, is not finding out they're incapable of love but rather accepting this and loving them from afar only to discover they're actually quite able.
In fact, that they're more than willing to die for a human they've only just known for several months, not to mention openly oppose the whole of the Heavenly Host and Fall and lose their Grace.
The problem is watching them get hurt over a human almost as spectacularly damaged as a demon, a human worth less of their time than a grain of dirt has on a diamond.
As if the diamond had gotten tired of all it's brothers, the rubies and sapphires and emeralds, and suddenly found it quite liked the change, even though Dean Winchester was a speck, a nuisance, filth merely masking some of Castiel's inherent beauty.
The problem is knowing at they're dying for a man who broke in Hell and tortured with the worst of those creatures, whose aspects and practices defined Hell as the epitome of pain.
The problem is that he'd figured Castiel wouldn't mind if he faked his death seeing as he didn't love Balthazar anyways, couldn't, was too invested in being the good soldier.
The problem was that he was wrong, and Cassie was wrong, and everybody was wrong.
The problem was that it hurt.
Castiel had been angry that he'd faked his death, but angrier still that he'd stolen so many weapons. What else was he going to do? Castiel was bright, but still forgot that Balthazar loved him sometimes, that Balthazar had never had interest in any of the weapons.
That the soul-dealing would gain Dean's attention more than Castiel's.
That was one of the few things he knew came from love - a need to drop everything you cared about and focus one what the keeper of your affections desired.
That if Dean cared, Castiel would have to care, too.
That he only ever did some things the Host ordered because Castiel insisted, that it only mattered to him because it mattered to Castiel.
Maybe he'd wanted Castiel to hunt him down, to chase after him for once.
It was too late now, in any case. What was done was done. Castiel had gone and fallen in love with a human while Balthazar was off being an idiot. Maybe that was why he wasn't more upset with the being who had been his friend for the better part of several centuries; it was his fault he left, wasn't it?
And maybe a tiny, selfish part of him still wanted to believe that Castiel was so upset about his death that the meager offerings of some hunter had gained his affections. It was mostly denial saying that, though, and he knew how denial worked.
He remembered telling Castiel.
That had been, as Castiel put it, "extremely unpleasant." whereas he, himself would say it was more akin letting hellhounds chew on his grace and then flambé it.
It was horrible, upsetting, vastly agonizing.
It had hurt.
Now he was watching the sort of quiet desperation that Castiel and his human displayed for each other, caught up in the struggle for control in a world anchored in chaos.
They'd revealed the chaos to each other, pulled the curtains apart and shattered the illusion they'd accepted and grown up with. Now they knew the truth, how unpredictable it all was.
And yet they held each other ever tighter, ever closer, like life jackets, even though they'd been the ones to jump off the boat in the first place, into the storm, acting like they could upheave everything and if they held on tight enough, they could manage.
It really wasn't a healthy relationship.
Oh, his and Cassie's friendship had wavered, on occasion, but it was stable.
Any problems arose from when he was being stubborn and refusing to follow orders - eventually Castiel would panic, would make it clear he would be very upset if Balthazar was smitten, and then he'd feel guilt, because he had been being childish and Castiel had attempted to shield him from a superior's wrath - or he would try to cut them off and stop himself from hurting because he loved Castiel.
That was always stupid, of course, because Castiel would never go to him begging him to return.
He was too respectful back then, too willing to assume Balthazar was being honest and truly didn't want to see him ever again.
Of course, he always dragged himself back to Castiel's side, and Castiel accepted his apologies without comment, would instead give that tiny almost smile and say, "I am glad you are back, brother."
It was later that he realized that maybe Castiel could, did have some potential to love him, so he'd stood back, waited for Cassie to come to his own conclusions, thought that would be better.
They were angels, after all.
The had all the time in the universe.
Until some pig headed hunter and his brother entered the picture.
Damn Apocalypse.