Edited reddit theory I posted (remember: I ship crobby so take this with a grain of salt):
So, my theory is that Crowley has been intentionally keeping Bobby single. Now before you say "BuT tHeReS nO pRoOf!!!", lemme matpat on yo ass.
Karen was the first of Bobby's lovers to die, and the only one to die of possession, which is strange considering that Crowley definitely either a: was very persuasive or b: had a position of high power in the crossroads department during the early 70s/ 80s so he could've commanded/persuaded a demon to kill Karen and we know crowley WILL NOT stop until he gets what he wants. Still not convinced?
After Samuel colt had invented the colt, I think it's safe to assume he would test it on everything to see if it really would work on anything. Gabriel (most likely bored as hell) decided to let Samuel test it on him. Why Gabriel? Michael doesn't want to die anytime soon, Raphael also doesn't want to die yet and luci is in the cage. So Gabe was bored and let Samuel test it on him after telling him he was an archangel. Long story short: it didn't work, Samuel wrote it in a journal and hid the journal away because he wanted to give the people some false hope if they found the gun and heard the lore.
Now, to season three/five. Crowley had found the journal and, with the knowledge that lucifer was an archangel, decided to hide it again (just waayyy more well hidden). Then Bela gave him the colt. Afterwards, the two idiots and the hot blonde needed the colt and Crowley decided to give it to them and instructed them to shoot luci. He then remained hidden as the boys arrived in that town and brought juliet with him, disguising her as one of meg's and telling her to go after jo. More specifically: to wound her and/or her mother so badly that they can't move or be moved. He then lied about not knowing that the colt wouldn't work to the fools (as the tarot card deck calls them). Why would he do this? Because he knew Bobby and Ellen would get together if she didn't die and we know that because Balthazar un-sunk the Titanic and Ellen lived as a result.
Now to season six. In weekend at Bobby's, LITERALLY the day before Crowley was in Bobby's basement, the okami that Rufus failed to kill attacked marcy, who had a blatantly obvious crush on Bobby. Isn't that just a little weird?
In season seven, Crowley only opted to help the boys with dick AFTER Bobby died.
In season twelve, Crowley or a minion could've eavesdropped on the boy's conversation about Bobby being alive in the apocalypse world and, by the time they had trapped luci in there, Crowley might've thought that Bobby had died cause it was worse than hell there and (after having enough of this shit) found an excuse to commit suicide.
Oh. And Crowley took a picture of the deal he made with Bobby, suggesting he enjoyed it, and gave Bobby's legs back out of sympathy, not because "the deal was trash" because he knew that if they succeeded (which he made sure they did) luci couldn't kill him cause he would be in the stuck cage.
But that's just a theory...
A FILM THEORY!
