Why didnt she just throw the gift away?

She's married now, its just best to let it go. It doesn't matter what her reasons are, she's married and that should be enough. Whatever your intentoins were it may have still caused trouble and she's mailing the stuff back to you to show the husband thats she's upfront and letting him know whats going on. If she needs vitamins, I'm sure she can buy more without sending her some. She is married now and you have to let it go.