I think it's lovely that your OH wants to take time off to be with the baby, but you may find that in reality the extended leave could be a chance for you to breastfeed a little longer. Until you have your baby and see how feeding goes it is too early, IMO, to plan this sort of arrangement.

However could your OH use part of the parental leave at the same time as you are on maternity leave to give you all time together as a family? That might work well without disrupting breastfeeding.