NYS is right (as usual) on this one. Bringing a third person into the bedroom only works if the marriage has a strong foundation and both partners agree that it is just for sex and fluff. Again...the marriage must have an unbreakable foundation.
HeatherG...I have to warn you....if the conversation keeps coming up wheter it is 1x a week...1x a month...or whatever...your H will feed off that fantasy. You must never feed into this fantasy. Communicate it how you want. You can ignore it when he brings it up...you can put the hand up because the face ain't listening..or you can get in his face and say, "NEVER". What ever your style is.....don't feed the fantasy. If H keeps bringing it up that means he is thinking about it and eventually it will envelope his thinking about you and your sex life. Don't let him use it as a tool you "maybe work things out". It is a trap.
Now...just because I know all this...doesn't necessaraily mean I've been there..................right.