There is a few extra things you mentioned such as, you only see him twice a week and I assume for the past 12 months.
That he watches porn "a lot" .
And then what everyone answered, alcohol.
Has he always worked away or for a long time? I am envisaging that due to his work he's been alone for a good portion of his life or hasn't been able to hold down a proper relationship. That Porn was his "sex" for a long period of time as well. And, that alcohol is a part of relieving his depression.
It's possible that he suffers from depression and is not happy within himself which started way before you entered the scene.
It would be good if you gave us some back-ground of what you know of his "before" life, before he met you. If he even likes his job or if it's just a job.
Drinking so much alcohol to the point of not being able to think and feeling sick the next day and doing it all over again, watching Porn, sounds he's in a downward spiral.
It also sounds as if he watches more porn that you would like him to, especially given that you are not intimate.
This has nothing at all to do with you.. Porn can lead to a man looking after himself and not needing sex if he is addicted to that, and addicted to alcohol, no one else matters in his life at present and he needs help.