I feel so sad for you,especially because you obviously did not fully enjoy your engagement party because of your Mum and Sister.Can I please give you a bit of advice which stems from a sort of similar situation ? When my then fiance and I wanted to get married we had months of turmoil wondering who to invite and who not to invite,as his Mum and Dad were divorced and could not be in the same room as each other.My Dad had died very suddenly a few years previously so I really wanted my Mum there,but then we had the thought that if my Mum was there,so should my fiances Mum.This spiralled out of control as we knew we would not have a happy day if there was a lot of tension in the air.In the end we got married secretly in our favourite place(Whitby)with just us,our son and two witnesses,whom we still keep in touch with.The reactions from family members were varied.One of my brothers did not speak to me for at least 6 months,my fiances Mum took it quite bad. Others were very happy for us.All I can say is that we are so happy that we did it the way that we did.We had a wonderful,stress free day,and even though we missed people,we knew we had made the right choice.