loopy it doesn't hurt to part mine either, in fact I'm sitting cross legged which I'm not supposed to do, but hey, it takes the pressure of my lower back/pelvis! I have PGP (newer name)- it's not true SPD, mine's all where your spine joins your pelvis (sacro something joint). It can cause pain at the front/inbetween legs if it's really bad.
Don't live with it though, that was my mistake with DS, thinking it was manageable then suddenly it really wasn't and I ended up in front of a class of 13/14 year olds in tears with the pain (who were lovely) then signed off!
mrsmummy, yeah they're pretty good- for that anyway, I could list many things they aren't so understanding/good about 