A sex-starved marriage can be very very very difficult. The person with low/no sex drive feels that they can completely regulate the amount of sex in the marriage and it's not fair and it's not what either one of you signed up for/agreed to.
I just don't think the swingers board is the best place to look for help in your situation. The divorcebusting boards or sex-starved marriage boards or no-more-mr-nice-guy boards will offer a much more positive outlook on your situation and how you can resolve things in a more positive direction.
I think that completely withholding sex or driving the other person insane with pre-conditions and charlie-brown-football-pull foreplay is just as much a lack of fidelity to the marriage as cheating. It can be resolved, but it ain't easy. *good luck*
Mr. FC4L