In Beelzebub's not so humble opinion, they were both idiots. Not in the general sense of the word, on the contrary, both Ezra Fell, Beelzebub's partner and the most adorable lawyer to ever pass the bar, and Anthony Crowley, the dark and dangly version of Atticus Finch, were very clever people. Somehow together they formed one remarkably hopeless idiot.
When Beelzebub, Ezra and Gabriel founded their firm, they were young, and at least Beelzebub and Ezra were wildly idealistic. Gabriel had the luck of being so ludicrously handsome that it usually took years to see how absolutely, utterly stupid he was. His looks could trick judges, opposing counselors, juries and what not. Beelzebub and Ezra knew him well enough to let him handle the easiest cases and made sure to write most of his arguments down for him. Gabriel was very good for obtaining the clients though, so this was what he had been doing. Beelzebub would take the most difficult, daunting, challenging and impossible cases and had never lost a case. What nobody outside the firm knew was that all that success actually belonged to the bookish counselor by the name of Ezra Fell, who would take pro bono cases and cry over them. He knew the law like the back of his palm, he rarely had to concentrate to remember something and he never had to look something up. He was invaluable. So, Beelzebub was actually delighted when they overheard a conversation between Crowley and Ezra on Crowley's first day, which resulted in Crowley's being smitten and foolishly in love and Ezra as oblivious as ever. Beelzebub couldn't be surprised by the fact that Ezra would donate his bonuses to all sorts of noble causes and Ezra didn't boast about it, he just was explaining something about a case and its particularities and how unfair everything was and how he had to make sure no such thing could happen again, and Crowley joked that this way all his bonuses would go to charity, and Ezra shrugged and said he'd been giving them away anyways.
The following years were full of wicked fun for Beelzebub. Crowley was as brilliant, relentless and naughty as Beelzebub themselves, but their utmost pleasure was to watch Crowley monopolize the cake supply on Ezra's table, bring Ezra delicacies and do everything short of just running around the office wearing a t-shirt with "I want to marry Ezra Fell and nothing can stop me" imprinted on it, to get Ezra's attention. The attention was received, but Ezra wouldn't grasp what Crowley wanted, and Beelzebub quite enjoyed seeing the most brilliant lawyer to have walked Boston being so oblivious it was almost unbelievable.
In time the betting pool was formed, and it grew every year, and every year brought exactly nothing but new cakes, rare editions of rarer law codes, oysters, champagne and taking care of Ezra's house, because the man couldn't understand many a routine thing, like the replacement of light bulbs and actually turning the iron off. Crowley had even run into Ezra's burning house to save rare law codes, because Ezra looked heartbroken. After that Ezra remained quite silent and pensive for a week or so, and the betting pool exploded, everyone hoped that finally Ezra would notice something. Ezra indeed noticed that he had been in love with Crowley but insisted (when Beelzebub insisted on them talking about it) that a man like Crowley in his dashing glory could never fancy a bookworm. Beelzebub actually replied that Crowley being a snake, there could be nothing surprising about finding a relatively similar shape of a worm attractive. "Oh, but I'm soft and plump and..." Beelzebub, on hearing this, rushed out to Gabriel's office and threatened to destroy his life if he ever body shamed Ezra again. Gabriel had been doing it since law school, and Beelzebub had been threatening him for just as long, but somehow that time it worked and Gabriel spent a month apologising. He even had the audacity to bring Ezra a cake, and was burnt to the ground by the yellow eyes of Crowley.
Anyway, as time went by, it imminently arrived at yet another Halloween, and Ezra suddenly announced he was going to dress up as a flamingo, and if everyone was thinking Crowley liked him, then they would be proven wrong, because unless Crowley came as a flamingo himself, Ezra refused to believe a thing, and Crowley would never do such a thing. Nothing could be farther removed from Crowley than something pink and fluffy.
Beelzebub made sure Crowley learned of that conversation. Crowley couldn't stand two implications: that there was something he wouldn't have done for Ezra and that there was something he wouldn't have done in general. Pink and fluffy? Make it two and add some extra glitter.
Ezra Fell had been wrong exactly once in his life. He thought Crowley wouldn't have done something to endanger his image. The fact that Crowley had endangered his life for Ezra's books didn't count because Ezra didn't count it. He was indeed quite oblivious.
And Beelzebub dressed as a fly rejoiced watching two flamingos, one of them lean and tall, another round and soft. Flamingos pined despite the fact that flamingos had nothing to do with pines. The lean flamingo put all his proverbial eggs in one proverbial basket and finally managed to ask Ezra out.
The next day Ezra was looking and behaving uncharacteristically wickedly, and Crowley had a dreamy look about him and a line of hickeys under his jaw. Beelzebub took that betting pool and began organising the wedding. Everything was ready just in time when Ezra just to prove everyone but himself wrong, proposed to Crowley, expecting to be refused, and was shocked and frankfully delighted to be accepted. Beelzebub then called the wedding planner they had hired and the flamingos were married within a week. Beelzebub discovered halfway through the ceremony that they were crying. They were still idealistic. They intended to keep it a secret.