No, not everyone gets it. Apparently the more quickly your tummy expands, the more likely it is to happen. Mine didn't separate with my first pg, but did with my second (and boy did my tummy expand quickly second time - I didn't put on much weight but my tummy was huge). If it does happen, you are limited in the exercises you can do for the first 8 weeks or so, and need to be careful lifting etc. Then Pilates type exercises are a good way to fix it, sometimes in bad cases surgery is required.