Disclaimer: Dialogue is not my strength
I think the problem is not that the dialogue is too long, but the fact that there's too much repetition and lack of variation. You do have some of the latter at the beginning and at the end. But in the middle, almost all the dialogue consist on two lines (and each sentences has pretty much the same length)
Another thing you could do is to write more "incomplete" sentences. That makes dialogue sound more natural and less formal (I think you're was a little bit too formal/academic).
If it was me, I would edit it like this. Hope it helps.
Jad's wiry frame barely makes a dent in the couch cushion and he's
jittery like he usually is when he's planning something. He reaches
into his pocket and takes out his stress ball, rolling it between his
hands like a therapist starting a timer.
"Given the evidence, I'm going to hypothesize Abby broke up
with you." he says.
"Yeah," I said. "According to her, we drifted apart over the
summer. When we were on different sides of the country. Now that I'm
back, she understands that it wasn't just the distance. She thinks
I'm not 'emotionally responsive' enough. What does that even mean?"
"Why didn't you ask her?"
"It's hard to think when your heart is shattered. What? You agree with her?
, I dare to ask, making an uncomfortable
amount of eye contact with him to read his expression.
"Ah, well.Want the honest answer to that question?", he
replies, continuing to stare straight ahead at the slapstick comedy
movie posters adorning our wall.
I grab another handful of jujubes in preparation.
"I think she means you don't connect emotionally with other
people. She maybe doubts you even know how to connect with yourself."
"Let's start with the first point. You don't seem to be able to
sympathize with anyone or to imagine anyone complexly."
"What? I understand people."
"The first thing you said after I introduced you to my friend Dev was
that he smelled pretty good for a hippy."
"It was a joke. I've never met a person with dreadlocks that
wasn't a hippy. Not like I told you he wasn't allowed in our
"OK, anyway. Second. What is it that you are actually working
towards? You hate your studies and you've never mentioned any side
“Why do I need 'work towards something'? Anyways,
even if you're right and I do need to fix these 'problems', what can I
do about that?”
"Okay. One question at a time. There's nothing wrong with being happy.
You asked about improvement in the first place. As to
what you can do about it. What do you want to achieve anyways?"
"Closure? I want to see if she's right, I guess. "
"Do you think she's right?"
"I think our old friend the scientific method could help here. What if
you tried being more caring? You know fake it until you make
it and analyse the results."
"How do I fake that?"
"You can try cognitive behavior therapy.”
“That sounds like something out of a self-help book.”
“Maybe there's something we can print.”
OK, maybe I messed up a bit the dialogue. But what I wanted to show you is how to apply what I just said. Also, keep in mind that not everything that your beta readers said is what they actually mean. For example, since your beta reader is a woman (I just assuming here, this may not be true for all people) she felt overwhelmed (or bored) by all the "logic" and "analysis" of the dialogue. I think most women don't like that (every time I start talking like this my girlfriend she starts yawning). So, since she felt bored, she felt the dialogue was very long.
And in some way I think I agree with her. I would rather prefer reading a dialogue strong in emotions and imagery rather than a dialogue that feels like an academic paper. This doesn't mean your dialogue is bad. I'm sure many people would prefer this kind of dialogue.
This is an example of imagery you could have used to "show" us how detached Tony feels:
"You know, sometimes I feel there's a thick wall between people and
me. And I'm holding this hammer, trying so hard to break it. Though
no matter how much time I spend on it, it never cracks. Not even a bit. I
want really badly to see the person on the other side. But I never
(Of course this is my style. You can use any kind you like).
Feel free to ignore the points that didn't make sense. And take those you think will work for you. Good luck!