It has become a thing in the secular world that a girlfriend would start wearing some of her boyfriends comfortable clothes while indoors (sweatpants, hoodies, t-shirts, etc). These are clothes made for men, although these can also be made specifically for women.
Is it mutar for my wife to wear such clothes of mine?
She should not wear these things since they are made for men, therefore essentially she is wearing men’s clothing, which is Lo Silbash. Although there may be people that will wear clothing of the opposite gender, it is hard to call this the accepted practice, because it is still cut as a man’s shirt or pants, and not a woman’s, meaning that it is meant for men, and worn by men.