You need to do the stability stuff with weights BEFORE you get pregnant again though. Although, for me, I still can't do the high weights because of the residual pubic bone pain from SPD. TBH - I still find it difficult to get up off the floor without making sure my knees are together

It wasn't too bad during DS's pregnancy and was kept managed with simple core stabilising moves - on hands an knees on the floor, extend left arm and right leg while maintaining a stationary frame. DD's pregnancy kicked it in earlier - about 20w and was worse with SIJ (sacroiliac joint) on top of the SPD. I needed to consciously turn on my core and stabilise before even taking a step.

This time - I already have low back pain and SIJ discomfort. But it is manageable and I have just started to do the core exercises again. I stabilise before each movement from stationary and carefully make sure my knees are together for most movements. I slipped the other day and my pubic bone was sore for a bit but not too bad - yet!!

So, technically, you are both right. It is because of the relaxin in pregnancy and once you have it, it tends to get worse each time. BUT core stabilising exercises can make it much more manageable. I couldn't do a pregnancy without them.