Alex has treated Alexandra like shit, he strung her along. He knew he wasnt interested from the start but kept saying how he just needed time, he likes to take it slow but he didn't really mean he liked to take it slow, what he meant was "I don't want you to get too invested because I don't want to see you on the outside"
He's consistently pushed girls away, been arrogant, talked over them and generally been unpleasant and condescending to the women he's coupled up with. He expects to be able to treat them like shit and then just placate to them and them to say "Okay, Alex" and just roll over. He's not expecting them to say anything back.
I think what's so annoying for me is I've seen him behaving like a twat throughout but I really wanted to like him, and against my better judgement assumed that he's just socially awkward but I don't think he is I think he's just your common or garden twat.
I can understand the turning away in bed because I would be very uncomfortable sharing a bed with someone I've known 2 weeks but he's acted like Alexandra is almost disgusting with his complete lack of physical affection. You can see Alexandra start to doubt herself and you can see how upset she is.
He knows how to do it because he can give Jack perfect advice, he was disappointed in Josh and was pretty much the only boy to think of Georgia. He knows how to treat women he just doesn't do it himself.