i am so sorry for the loss of your twins
fortunately/ or unfortunatley for you so women just tend to ovulate on both sides or more than once in their cycle. Also they have found a genetic link to having ID twins as well.
I do know women who have had a simliar thing happen to you as they keep producing twins as well as m/c twins as well.
have they tried to find out why you m/c rather than the fact that you m/c twins? maybe if you can get some answers, it may help out!
good luck with this journey and know that there is always someone here with an ear to listen and for you to talk to - including me\
take care
odette