I would hope that he is 'just' very immature, and in a few years' time, once he's grown up, he will look back on this open-mouthed and realise what an absolute piece of work he has been.
Then again, he may well not, and this might be as mature as he ever gets, with him simply incapable of ever being a basically decent human.
Either way, you deserve so much better than him, and you are NOT his therapy, even if he does make that journey and come out the other side, a proper adult, feeling mortified and fully contrite at what he said to you.
Most definitely send him packing (in both senses of the phrase) later this morning and be kind to yourself. Don't rush, and be patient until somebody who IS worthy of you comes along. You are still young and, as PP said, you hopefully have 60 or more years ahead of you to make a lifetime with the right person.
You find it difficult to make friends because, gently, sometimes we just do - especially those of us who are naturally introverted. It can be a very positive thing, as it just means that you have high standards and are unwilling to settle for second-best. And it is highly likely that, once you do find genuine friends, even if only a small number of them, you will end up amazing, close pals who will stay together for a very long time, maybe forever.
There's every chance that they too have been struggling for some time to make friends, and fearing that they never will - and you will all, in equal measure, feel so happy to have finally crossed each others' paths and found one another, in it for the long haul together!
It's a cliche, but it's nevertheless true, especially for you right now: once you have said a firm goodbye to Mr No-Empathy-Baby, today really is the first day of the rest of your life - so make the very best of it and don't let any immature idiot treat you as his doormat.