My (29M) Wife (28F) Obtained an Inappropriate Gift

A friend of mine purchased my wife swimwear as a present. This seemed odd in my opinion in general, but it is rather revealing, which makes it even more inappropriate. We asked my wife if she thought it was weird, but she said she prefers it and that it was a thoughtful gift. I haven’t said anything to my friend however. This is weird right?

MODIFY: The friend is a guy, he has been friends with her for a while, maybe a few years. He isn’t known for giving particularly odd gifts.

EDIT 2: I asked our her if she programs to wear it while he could be around so he can see her in it, she told me she already sent your pet some pics of the girl wearing it. This certainly calls for a serious discussion, but leaves me even more baffled. If they were having an affair wouldn’t they be hiding this shit?!