Big hugs mama. Don't they know that of course they are right... I mean, of course the whole reason you got pregnant at all was just so that after you had the baby, you could flash half of a breast at her hubby and her while breastfeeding
I know it is so hard, but pp are right, this is about them. I had friends say wow we were shocked when we were all eating dinner at your house that you nursed at the table. And I said well every time the baby smells food he wants to eat too, so get used to it! lol
I was a bit taken aback at first myself, when they said that to me, but I knew I wasn't doing anything wrong and realized it wasn't my issue. It just takes some people awhile to warm up, especially if they haven't been, forgive the word, exposed to breastfeeding themselves.
I strongly suggest taking this as two people who are confronting something for themselves, and as a chance for yourself to firmly feel and decide that you are doing what's best for you and your baby, and you are really okay with it. Though it smarts now, if you don't see this as anything but a chance to feel more sure in yourself, it will blow over, and most likely in the future they will feel like asses for saying anything. Even if they don't, their thoughts have nothing to do with you and how you should feel and conduct yourself.
Love and hugs to you, mama.