Am trying to put this calmly and be factual - sorry it is bloody long!
Friend is in a relationship of 3 years. Both full time working professionals in their mid-20s.
He owns a house, lives there and lets out the other rooms.After a year ish of seeing each other a housemate left and she moved into the empty room. He was always "not very emotionally articulate, can only think about one thing at a time, doesn't put things very well" (her words). She hoped that living together would make things easier- she was often upset by his unthinking behaviour. He wouldn't come over to her house much (as his PC was at his.)
When she moved in there was no celebration - he told her "just because we live together doesn't mean we'll be spending any more time together". He has mentioned his "mad, clingy exs" and so she is at pains to prove she is independent, not needy etc.
Recently she was using his PC and when searching for something else the history revealed he had been looking at porn - something that is not illegal but which she found upsetting and disturbing.
She spoke to him about it and explained her feelings- that she found the material disturbing and that it felt insulting to her as she has been making an effort re sex and he has been disinterested. He said "I didn't look at what the film was called- it's just bums and boobs".
Any further upset on her part he deals with by saying " I can't handle all this emotion over nothing."
He spends several hours on his PC with headphones on playing games online. She is not to interrupt him- he tuts at her.
Recently she suggested doing something together that evening- he said "but I spent all weekend with you"
When living separately she suggested seeing each other on an extra night as they were both unexpectedly free - he said "but I don't need to see you tonight- I saw you on Sunday".
She was very upset one evening after work- she has a very intense job- and called him to ask if he could come home- she needed a hug and a chat. He was with friends playing a board game. He said "no- this evening has been planned for ages and we're in the middle of the game" She was in bits. But still said " well I understand he didn't want to let everyone else down- they can't play without him".
She said that he is a nice person:
"he plays squash with me sometimes,even though I'm not as good as him" (she actually took up squash to spend more time with him as non of his arrangements are negotiable).
"He cooks for me sometimes- though he does really like cooking"
"He just doesn't put things very well/ has the emotional range of a teaspoon"
These are just a few examples.
She has been to counselling - and keeps saying how relationships need compromise (very true!) and that she needs to change too. Though sometimes she says if she changes anymore she won't be her 
Her DM and aunt say "he's a nice lad, it's just how he is, he doesn't mean it." Her DM is desperate for GC too... They like to brush difficult things aside and this makes me doubt my feelings on it- hence MN...
I feel so sad for her. She is clever, pretty, sporty, generous, caring... I try to listen and not get over involved, not have a go at him- she loves him and I don't want to make her feel bad for that.
I have said that he isn't going to change as a person, and is this what she is prepared to settle for?
Every time she goes back, has a chat about "the change needed" and then it's fine for a while, then straight back again. She seems to be trapped by her low self esteem.
IMO he has a tenant who can be his girlfriend when it suits him. He never has to say no to anything he wants to do, never does anything he doesn't want to. If she objects she is needy, and he says "we're not like other couples"- too right - there's a reason for that!
What can i say/ do/ be?