"Wasn't the point of free will that you can choose what you want to do? Isn't that your humanity, Cas?" Dean shook his head, rubbing his hand over his face with a heavy sigh. "I get it, okay? I'm some huge asshole for havin' a bunch of old feelings that just won't quit. And I get there's a whole world apart from Jo and Meg."
He picked up a wrench to toy with it, distracting his hands as he thought about it. "I mean, Jo's... she's awesome." He half-smiled, looking towards the house briefly. "She's full of fire, even if she's still pretty green and too bull-headed to realise she is, but she's always been her own person. Hell, she never put up with my crap. I get it, she's a... damn amazing girl." He looked down at his wrench, turning the tightening bolt on it.
"Then there's Meg. She's been a royal pain in the ass since what feels like Day One, but she's nothin' if she ain't loyal to you. She doesn't have to be. But the demon thing, man, it still bugs me. Even if somehow she and I are friends or somethin', now? I don't know, that creeps me out. A lot." He laughed a little, letting it fall flat.
Pushing off the car, Dean stepped close to the angel. "All I'm sayin' is you pick who you want. I'm not gonna stand in your way with either of them. Meg's more than she lets on she is, she's got a heart under all that... thorny beauty, and Jo's always gonna mean a heck of a lot to me, but man... Cas, come on, we're family." He gave him the best attempt at a smile he could manage, which also fell flat. "If I can forgive the crap that's happened in the past, I can forgive you knockin' boots with a pretty important old flame of mine."
He let his gaze become a little more steady and serious. "I just can't forgive it if it's gonna drive a wedge between you and me. Next to Sammy, you're... all I got, Cas. Mandalus, it ain't real, it's a pit-stop in the uphill fight. When we get back home, when we're both out of Purgatory, together, there's gonna be you, me, and Sammy. Team Free Will, remember?"