How long has she known this person?
What are their ages and your age?
How do you feel it raises questions?
How long have you been married?
Thank you for that additional info
Was it a new item or a used item (ex; something she was getting rid of)?
Have you spoken to your wife about how you feel? If so, what was her response?
Was the gift given in front of friends and neighbors?
Have they given each other gifts in the past?
Well, on one hand, women tend to give each other gifts like this without taking it personally. I was given a vacuum cleaner for Christmas, and didn't take it as a sign that my house wasn't clean, but by the same token, I had mentioned a few times that mine had died, so although it was unexpected, it was given with the knowledge that I actually needed it. However, I don't equate the vacuum cleaner with personal hygiene, unless there's a back story to go along with it, ie; she's made comments about dust in the house, or the floors not being clean, or the two of you are not on the best terms and you feel it might have been a dig towards you. I do find it interesting that she gave a vacuum cleaner and a dust eater, like there's some type of message there.
If your wife agreed to return the gift, it may be that she in some way sees your point. You are right in allowing her to have her friends and her space, many people disregard that to the detriment of the relationship.
I hope this helps. I welcome your thoughts, let me know if you want to talk more