I agree with Michelle C... when he's 'doing the do' to himself, join in, it should get him going a bit more and will certainly turn you on too. Maybe invest in a sexy outfit, a french maid perhaps.. I got mine from Ebay for only £15 and it's really nice, sexy, not ott. So picture this, your hubby is 'doing the do'.. you walk over dressed in a sexy french maids outfit, you 'help him out' .. the whole experience will be both visually stimulating and touchy that you could be in for a great night / day of passion.
You could also pleasure yourself in front of him (in your new outfit) and tell him to come join you, I bet he doesn't hesitate.
If you feel too embarassed to do all of this..just remember your frustration of this whole situation and 'just do it' I can almost guarantee your hubby will respond.
I did it and our sex life is now really good, went from quite boring and not often to very unboring and much more often.
Let us know how it all goes and good luck with it.