MAN TOO MODEST FOR SEX

I am in love with a man I met in my hometown. Before spending any time alone we talked on the internet, internet sex and fantasies.  The talk was so hot I couldn't wait to get together with him.  He did admit that his last encounter was 10 years ago and ended badly. This made it more intriquing knowing that he was not out jumping everything in sight.  During our first time alone at my place four months ago he was nervous about even getting undressed and very shy.  He was not at all aggressive and I had to do everything.  He did not get a full erection so no intercourse took place. I have been very patient and understanding but this has not changed.  We spend about 12 hours a week alone at his house but he has only tried to have sex four times and each time the erection is not sufficient for penetration.  He even has me cover my eyes while he  takes off his pants.  He is young and very physically fit.  The last time he was very passionate and seemed really turned on but did not get a full erection but ejaculated anyway.  He was very embarrassed by this and said it was the last time.  I tell him that the important thing is that we are together and that we keep playing,  but every time he gets aroused he walks away and looks at the computer and starts talking about his blog or whatever.  He avoids talking about personal things and will not talk about this.  I don't know what to do because I feel he is shutting me out because of this sexual dysfunction.  I have never encountered anything like this before and don't know what to do.  How do I get this very private person to talk about this without scaring him away or do I just keep quiet and see what happens next?