do you really think dean is aro? no judgement, it's a cool thought, i just can't reconcile it with all his secret desires for romantic picnics and an apple pie life
My answer is a little complicated, anon.
Essentially, yes, I headcanon Dean as aro/arospec. But this is a headcanon, not what I think the show intended as canon; much as I'm sure it wasn't their intention to canonize Sam and Dean as a queerplatonic life partnership, nevertheless they did, for those of us who know and appreciate what that is.
I've seen arguments for him being frayromantic (when someone only experiences romantic attraction towards those that they are not deeply connected with, and lose that attraction as they get to know the individuals), and that lends itself well to the way Dean has been shown to be a very romantic lover, I suppose.
But I tend to think of him more as greyromantic (feeling romantic attraction rarely/infrequently, and only under certain circumstances). I think this can account for Cassie and Lisa, and lends itself well to my SamDean headcanons.
Now, as for "all his secret desires for romantic picnics and an apple pie life," I personally think this perspective only works if you haven't finished the series. Particularly if you haven't gone past season 5 or 6.
Now, in s2, we get a glimpse of this idea of Dean's secret "apple pie" desires in What Is and What Should Never Be. But that is less about Dean's romantic desires than it is a manifestation of his boyhood desire for his family to not be affected by the supernatural. For he and Sam to have grown up in a normal, stable family (with normal chores like mowing the lawn for your mom, instead of cleaning the guns for your dad), and for Dean not to be the reason his dad is dead. And once again, Sam is the one with more of an apple pie life, whilst Dean has a reputation for drinking and doesn't have a relationship with Sam.
In s3, we get Dean's dream about Lisa and the picnic. This dream often leads to the interpretation that Dean loved Lisa the whole time, and sometimes causes upset at the apparent slighting of Cassie as Dean's first/true love, but I think it's a mistake to take this dream at face value -- dreams rarely are just what they show, even if spn tends to be heavy handed in their storytelling.
-- again, I think it's less about Dean's romantic desires, and more about the idyllic life he's never been able to have -- and won't get a chance to because of his Hell deal. Lisa is the one in the dream because of that split second where Dean thought Ben could be his son-- in the middle of this middle class neighborhood with a bouncy house and backyard bbq-- and he imagined an entirely different possible life for himself if he wasn't a hunter headed to Hell. Dean is easily baby-trapped, lbr.
Being aromantic doesn't necessarily preclude fantasizing about being able to be romantic, either. Especially if a person is still on their journey of self discovery. Sexual and Romantic orientation are a spectrum, too, and sometimes that spectrum is traveled throughout one's life. And sometimes we spend time fantasizing about the ability/ideal to do what is socially expected of us.
But the Dean of mid-to-late seasons doesn't really show a desire for an "apple pie life" beyond his belief that he wants Sam to have one. He doesn't talk about settling down himself, or show a desire to build lasting romantic relationships with anyone other than Sam, who he married in a handfasting in Sacrifice.
And when Sam asks Dean in Baby if he never thinks about settling down-- well, actually, here's how that post-Piper scene goes:
SAM: Dean, I can explain what was going on --
DEAN: No, no, no. No.
SAM: Don't "Night Moves" me.
DEAN: Shh. Just let it wash over you.
SAM: Let . . .
DEAN: Just take it in.
Bob Seger’s “Night Moves” plays on the radio.
[The Night Moves interlude, my beloved...but cut for length.]
Let's take a moment here to appreciate Sam's apparent need to explain himself to Dean. 👀
SAM: I tried to give her my number. You know what she said?
DEAN: "We got tonight. Who needs tomorrow"?
SAM: Is everything a Bob Seger song to you?
DEAN: Yes. Well . . . [ sighs ]
SAM: It was nice knowing you, Piper.
DEAN: Piper? That's awesome. Heather. One-night wonders, man. Shoot, we're lucky we still get that at all.
SAM: Really? You don't . . . Ever want something more?
DEAN: I'm sorry, have you met us? We're batting a whopping zero in domestic life, man. Goose eggs.
SAM: You don't ever think about something? Not marriage or whatever. But . . . Something? You know, with a hunter? Somebody who understands the life?
DEAN: Have you not heard a single word Bob's been singing about?
And Dean leaves it at that, but it's pretty clear romance is not something he's really thinking about. He's seemingly fine getting even the small amount of "one night wonders" that 'they' do get. (Another moment here to appreciate that Dean's pronouns are we/us, in a SamAndDean kind of way. --and that this conversation takes place over the course of a very domestic montage.)
Now, granted, at this time they're dealing with the release of the Darkness and all that entails; and granted Dean has been dealing over 3 seasons with the perpetual idea that he should expend his life and soul for the sake of Sam getting that apple pie life; but Dean seems to have left those "domestic" thoughts behind even before he had Castiel wipe Lisa and Ben's minds in s6. Dean's primary domestic relationship is with his brother, and as long as Sam is there, that's alright with Dean.
And what does Amara give Dean as his reward for helping her with Chuck in s11? Mary. Ignoring the later reasoning/retcon that she did it to teach Dean some lesson, we can say that once again Dean's domestic desires are pinpointed as having a fulfilled family life, but not necessarily romantic fulfillment.
And later, when Dean's "greatest desire" comes up again in Lebanon, what does he get from the pearl? He gets his father and mother, alive again under the same roof as him and Sam (and if you want to give subtextual meaning to Doylist ~fanservice~ concerns, wished it so that John and Sam would get along better than they would've if that were the actual 2003!John).
All this, and the fact that he and Sam continued to live and hunt domestically after Chuck was gone, are why I like to headcanon Dean as aro.