Hi Marco,
I know I am late in responding to this thread, but I still hope you read it. You have gotten alot of wonderful in depth, great advice from Anita and VJ. I am going to keep mine simple. You may not agree with it, and that is okay, for it is only my opinion. It should not be tolerated whatsoever what your family, sisters are doing. It is wrong. You do not do this with their spouses and families and they should not put you and your wife in this situation. It creates too much conflict, awkwardness, hardship for your wife, etc. Being around your sisters, although they are blood, is allowing them to create negativity to you and your wife. Blood should not treat blood like this. But I have heard people say that they have had strangers treat them better than their own family.
I would not cut your sisters out of your life completely. But just let them know you will not and can not tolerate this form of treatment from them. Whether it is envy of you, the universe, or whatever is going on inside of them, you have no control over it. Talk to them on the phone, text or e-mail. Make it short and polite. Don’t talk about your wife. If they do, say “I will no longer engage in this negativity, treating my wife with disrespect, is treating me with disrespect” and say you have to go. End the conversation. No one says you have to visit them. It’s you and your wife or nothing. Their treatment should not be tolerated. In time, they may change. They may miss their interactions with you, and will need to accept your life. They will learn to get over themselves, everyone has flaws. If they come around, that’s great, if not, enjoy your wife and her family. God bless.