Is there any way to stop jealously between my huskies?

I have 2 husky pups, male and female siblings, who are both 6 months old. They are being neutered and spayed this week so I am praying this behaviour calms down once this gets done, but anyway, the male is definitely the most dominant out of the two of them and is very possessive. They will allow me, my boyfriend and anyone else to take toys from them, go near their food and even put our hands on their food bowl without so much as a growl; they do everything we ask of them as we had them trained professionally so on the whole they are great dogs. However if the female so much as walks in the same direction as something that he thinks belongs to him, he will either growl at her or launch at her and they fight. We can buy them identical toys, but he isn't content with having just one, he wants her toy too. He thinks they are both his property and won't allow her to touch it without either a "back off" growl or starting a full blown fight with her. This doesn't happen on a weekly basis or anything, but has happened probably about 3 or 4 times since we got them. Yesterday, we gave them both a ball each to play with and he instantly attacked her when she picked her ball up, to the extent that she was yelping like crazy and we thought he was going to take her eye out because he was biting down on her face. No blood was drawn so I guess that's the only positive thing about it. As soon as we ordered him to stop, he did as he was told and stopped but I am getting sick of this. I have tried sitting between them when we give them toys and telling him to leave her, which he always does; however if we take our eyes off him for so much as a few seconds he will go and take whatever she has got. Usually she will give up without a fight but obviously some days she won't be so happy to give away what she has and that's when he gets mad. Is there anything I can do to stop this? I won't get rid of one of them, that is literally the LAST option before I have tried everything else I possibly can try, so please don't suggest this. If anyone can offer some suggestions that are actually helpful and not abusive, that would be great. I would also appreciate no answers that consist of something along the lines of me being incompetent as an owner because if that was the case, they wouldn't obey anything I said.