I continued to breastfeed through my second pregnancy, and beyond. Pregnancy number 3 was a different story though. Around week 17 it became apparent the milk was gone. DS was not nursing the same, it felt 'wrong'...and so began weaning. By 35 weeks we were no longer a breastfeeding pair. I was sad, as I had expected to continue and tandem feed as I had done with the first two. So I guess in answer to the OP, weaning began 15 weeks post ovulation.