So sorry to hear... I'd feel really rejected too...
It sounds like you've opened the door to talk about it on more than one occasion, but that he's shutting you down.
You need to find a way to insist that he have a talk with you about this.
Would a change of locale where you're to talk help any do you think?
It's a difficult situation considering he won't talk about it.
I sometimes visit Natalie Lue's blog called Baggage Reclaim. It's about relationships.
I just googled the following "husband doesn't want sex Natalie Lue" and some interesting articles came up.
Don't know whether they would help.