Swap Sect by Tony Calvano

From the back:

Sinburbia... to shatter the boredom of their frigid existence, Matt and Maura Arrow were easily led into the dark recesses of the wife-swappers where no holds were barred for shame and the only password was degredation. As the couples pared for depraved Lesbian encounters or donned the evilly contrived rubber garments, no sin would be postponed. They were all hellbound to make each meeting a perfect - lust orgy!