Crowley's always thought that he would never get to talk about his and Aziraphale's relationship. It was just unrealistic - whatever his feelings were (unconditional love, longing for affection, fear of loss), and however he chose to call them (lust, possessiveness, anger), he's always told himself that he should deal with it on his own. Go seduce some priest into fucking him and imagine white curls and a bright smile, sleep for a century and never use the word "fraternize" again, get some plants to yell at for not being good enough.
In his world, there were rules. Hell doesn't send strongly-worded letters, so be careful. Humans and animals don't deserve to suffer, so find a way to do your job without hurting them and preferably have fun while you're at it. Aziraphale is an angel, who is loyal to Heaven - at least on paper - and will not do anything that he won't be able to explain to his Higher-ups, so don't put him in a situation where he can choose to enter a relationship that will ultimately lead to him losing Gabriel's favor. Aziraphale is also your only friend, so do whatever you need to keep him around.
It's easy for him now. He's admitted his feelings to himself after the first millennia on Earth. He learned not to hate himself for them and cope after the second. He learned not to hope after the third. He learned to love without wanting anything in return after the fourth. He learned to show it in his own way during the fifth. He learned that he was quite happy the way things were during the sixth. So now he was a very well-adjusted demon, who knew his way around the situation he was in. Until Armageddon.
Crowley doesn't like to think about the day it all could have ended. He still has nightmares full of fire.
He hasn't thought about other things as well, apparently. Because he was absolutely unprepared for a situation he was in at the moment.
Aziraphale was standing in front of him, his hair whiter than usual under the moonlight, beautiful as ever among the trees of the park they were both standing in. He was looking at Crowley with determination and badly-hidden nervousness, and Crowley wanted to ask what was going on with him, but Aziraphale beat him to it.
"I've wanted to tell you something," he said. "Our situation has changed, obviously. For six millennia we've been here, Hell and Heaven breathing down our backs, but now it's just you and me. Our side, as you like to call it."
Crowley frowned, feeling a bit defensive over the "as you like to call it" bit.
"Right," he said slowly.
"Well, I've been thinking," the angel continued. "Since we're technically free now and both sides associate us with each other anyway, I don't really have a reason not to tell you how much you've come to mean to me."
"Uh-huh," Crowley said.
"You see, despite us being formal enemies, I've always felt you were special to me somehow. You were the only constant in my life here on Earth. And, forgive me if it still offends you, but I saw the kindness in you since the very beginning. Your ingenuity, your intelligence, your helpfulness, the extent to which you are willing to go for things you care about have all lead me to see you as a wonderful person whom my heart chose to love above all else. And I know that you enjoy my company as well and that you've wanted me to be closer to you for a long time now, so I ask you to forgive me for pushing you away. I couldn't bare the thought that an association with me could lead to Hell executing you."
Crowley swallowed a lump in his throat.
"'S fine," he said, hearing his voice break a little bit.
"It's not. But I hope we'll never end up in a situation like that again, and if we do, we'll figure something out together. I would also ask for your forgiveness for not running away with you despite you inviting me twice. I assure you that I would go anywhere you said if I really believed that we'd be safe out there. But as it were, I had to try to save this planet from destruction - not because of my kindness, but because I wanted to keep all those things you talked about: food, books, music and your company."
"Sure," Crowley said, feeling his eyes sting. Thank Whatever for his sunglasses.
"I'll try to make it up to you," Aziraphale said. "If you let me. Because, no matter how terrified I am of saying it, no matter how many centuries pass, no matter how hard I try to hide it, the truth won't change. I've known you for six millennia, Crowley, I've seen every aspect of you, I've seen you grow and change and become the glorious bastard you are now, and I love you, Crowley, for all that you are, for all that you've done for me, for all that you've changed in me. Nothing succeeded in stopping this feeling - not Heaven, not Hell, not myself in the lowest of moments, not Time itself nor the End of Times - on the contrary, I feel like my love for you contributed to stopping the End of Times instead."
Crowley inhaled shakily and nodded, not trusting himself with making dignified noises at the moment.
Aziraphale wiped at his cheeks where a couple of tears have escaped from his eyes. Belatedly, Crowley realized that he wasn't the only one who was trying to hold his composure against a flood of emotions that finally broke their dam.
He cleared his throat and stepped closer to the angel.
"I didn't prepare a speech for you, so sorry for shortness, but you're great. Love you too. Can I hug you?"
"Yes," Aziraphale smiled, wetly and brightly, and reached out for him first.
They stood there, holding each other for the first time since the Beginning, and Crowley couldn't help but wonder how the fuck he was supposed to live now. Beyond the sea of feeling he was trying to stay afloat in, an overwhelmed logical part of him who made rules was trying to make sense of life again. Hell could go fuck itself. He didn't have a job. Aziraphale was in his arms, sniffling ungracefully into his shoulder, because he just confessed his undying love for him. Nothing made an ounce of sense.
Crowley separated from the angel just enough to see his face, and took off his sunglasses, dropping them on the grass carelessly.
"I love you," he said, taking Aziraphale's face into his hands, feeling the angel's arms on his waist pressing them closely together. Aziraphale chuckled at him wetly, his eyes still shiny and his smile positively glowing. "I love you," Crowley repeated, running his thumb over a slightly wet cheekbone, because it felt very good to say out loud, after so long. "I love you," he said, pressing their foreheads together and squeezing his eyes shut. "I love you."
Aziraphale sniffled and nodded just a tiny bit, running one of his hands up and down Crowley's back.
"I'm unemployed," Crowley said, surprising even himself by latching on the urge to get things out of his system. "And Hell can suck it."
"Heaven can very well go fuck itself, too," Aziraphale said, surprisingly harshly, which made Crowley lean back just to stare at him. "What? It's not like it's in my job description not to swear anymore. I don't have a job."
"Are we," Crowley said, "are we retired?"
"We should buy a cottage on the coast," Aziraphale suggested. "How do you feel about a little garden?"
Crowley's heart begged for Crowley to stop feeling so many things at once, as he gave a little laugh and felt tears finally go down his cheeks. He clenched his fingers in his partner's coat.
"It sounds like a decent retirement plan," he said. "How do you feel about marriage?"
"No churches, maybe a reasonably corrupt priest, probably near the sea, and we need to make some friends to invite them to the ceremony," the angel replied without a hitch.
Crowley kissed him.
Aziraphale reciprocated with such fervor that some part of Crowley, the one that whispered to him that this whole situation wasn't to be trusted, finally gave in. And, as it did, he felt so absolutely swept with all of it, that something in him finally broke and he gasped into the kiss, his hands flying to the angel's cheeks to hold onto.
"You are the love of my life," Aziraphale murmured against his parted lips.
"You'll give me cavities with all the sweet-talk," Crowley managed.
"Good," Aziraphale responded. "It's about time."