Do you think a woman should buy lingerie to wear for her man or he should buy it for her?

I think him buying it for her kinda defeats the purpose. A woman should be able to make herself sexy for you if she wants to. If she doesn't want to, it kinda makes no sense to pressure her, i wouldn't enjoy it. The exception would be if she hints she wants you to buy something for her cause then she probably wants to get a feel for what you're into.