You have to be up front and honest with him....because you want him to be with you. You should bring the undies to his attention and ask him why they are or why he thinks they are in with his stuff. If you have any suspicious that there is something going on, pay close attention to his body language and the tone/pitch of his voice. Those two things tell all. If he does his laundry in a laundry room, then it could have been a mistake.....it is easy to miss a pair of undies when pulling clothes out of the drier.
