Considering you share sleeping arrangements with your wife and don't plan on winter use this discussion might be interesting
http://www.backpacking.net/forum/ubbthreads.php?ubb=showflat&Number=182412#Post182412. Just make sure your pads have somewhere near a 4.0 R-value to insulate you from the ground and the quilt is wide enough for both of you. In the end it may save pack space, money (especially if you sew your own), and be comfortable, too.