You know, this is the saddest thing. Bringing someone else into the family circle can be a tricky thing. You probably are so different from them, maybe why your husband was so attracted to you in the first place but your differences make getting along hard.
Yes, it would hurt my feelings too but have you asked them what it is they are upset about and if they can forgive you and move on for the sake of your husband?
Love always softens things. Try not to be angry but keep saying or doing a loving thing every chance you get towards them. Hate does not win after all.
Send a nice note, birthday card, say a kind thing, compliment when you speak to them no matter how much they don't deserve it. Thank them for their opinion even though you hate it.
They are probably thinking they are in the right for their judgments so instead of trying to change them, or change you, try just being additionally forgiving and loving.
So in then end, if they do not bend, you will have no regrets because you have made every effort to be kind and loving and your husband will respect you for it. It is not fair of him though, to always expect you to be the one that gives in so be strong here and know your boundaries: When to step out of conversation, out of the room, out of the visits.
He loves his sisters and it is okay if he goes sometimes by himself but not always. You are his companion and his strength and he needs you too.
Just to let you know, I have seen a family I love dearly fall apart because of just this thing. They become a divided family and lose the love that should be theirs. Instead of embracing the in-law, they made her an outcast and later she divided the family. I am so sad because it didn't have to be that way. It was hardest for the son and he finally had to choose and it broke his heart.
I pray that things will be better for you and God will bless you with love.
Please read about Ruth in the bible.
Love to you, C.