I suspect that you have got into a viscious circle - he knows you are really worried about this, so he is worried about you being worried, and the more you try to deal with the problem, the more aware he gets that he is worrying you.
I can't suggest any easy answers, excpet considering some kind of therapy that you both trust, but you may have a job to get him to agree. It may help to give up talking about it with him for a while, though.
I had a similar problem with my now Ex wife. Overnight my sex was gone one year and the more I got worried the worse it bacame. On my birthday, my ex quietly brought her sister to fool around with me and her. I had the first hard on in over a year.
After that hot nite, my sex life became better. I do not know your b/friend situation, suffice to say these things happen. The problem I found in my case was that the pressure just made it worse for me initially.
You sound like a nice girl. Maybe thats the problem? Buy a large vibrator and make sure he catches you using it one night. Then suggest he helps you by holding your hand/breast/legs up etc.
Or just to have him there and watch.
Maybe being Mrs Homemaker isnt the answer, maybe being a slut in the bedroom is the answer, but go easy to start.
Do something crazy-kinky ....that'll get his attention.