Before 12m, my mother/sister asked me to drop beastfeeding (similar reason, e.g formular provide better nutrition, etc) and my hubby wanted too but afraid to ask me. Even though my will are very strong, I haven't debate with them (don't want to waste my time). I have only speak honestly to my hubby my will to feed by boy over 1 year till naturally drop.
My plan is let doctor to say to my hubby, let him know the truth from professional. Therefore at 12m when we come back to FHS, I intentionally showed my worriness about the under-weight problem of my boy (actually I'm not) and ask nurse to arrange us to have doctor consultation. Luckily, both nurse and doctor encouraged me to continue breastfeeding and pointed out that this will help my boy reduce the chance of getting sick (thus, reduce the chance of losing weight). Since then, my hubby says nothing about my nursing. For my sister/mother, I then told them the doctor's opinion (I pretend I just follow the advice of doctor) and they can't say anything to convince me also.
To me, even the doctor/nurse ask me to stop, I've prepared to have a battle with my hubby/mother/sister. Luckily, my "plan" work finally and I don't need to face such battle~