While we understand that subs are not designed to be confined into an area, I think we all also understand that compromise is the key to any successful HT when men and women are both involved in the planning. This means not all of us can have 4 huge subwoofers laying around in the room, all seated in the position which brings out the best from each of them. It also means that quite a few of us won't even have the privilege of having one huge box laying around in it's perfect position. So while the advice being given says, "don't do it", my own theory is, "a subwoofer stored away in a cabinet, a closet, or some other subprime location is still better than no subwoofer at all". Don't worry friend, many of us here are married, so we feel your pain!
An alternative that is seldom brought up around here is, getting an 'in-ceiling' subwoofer. Axiom doesn't make any, but you can find them. If you have access to your attic, this could be a great compromise for you. You could place one or two of them right above your seating position, or in any other location you desire. Placement does present a bit of a problem as it becomes very hard to experiment with where they might sound best. After all once you cut a hole in your ceiling you're pretty much committed after that!
But they are at least out of sight!