Weight loss problems

My wife and I began making a conscious effort to lose weight about 7 months ago. We changed our eating habits and immediately lost about 30 pounds over about 3 months. We began adding an exercise routine that started with walking, running (treadmill and terrain), Pilates, strength training with weights twice a week, and some minor aerobics. I have continued to lose weight and to date have dropped about 55 pounds. However, my wife stopped losing weight after the initial 30 pounds and has gone back and forth between gaining 3 - 5 pounds and losing 3 - 5 pounds. Essentially, she continues to break even. She eats the same (if not better) as I do and she does the exercises with the exception of a lot of running(she does the strength training 2 times a week, walks 15 flights of stairs at her work each day, does occasional aerobics and Pilates, and walks (sometimes jogs) on our treadmill for 25 - 35 minutes a day. She lost several sizes in her clothing when she fist lost the 30 pounds but now, that has stalled as well. She's becoming really frustrated and I've been trying to be supportive. Any help would be greatly appreciated. Thank you in advance!