I think the slang term for this is "spiking" and from what I can tell, there are a significant number of people that like this. So your wife is far from alone.

Do a search onstrapon. There are several threads.

i have done it to a couple guys in the past myself I dont love it but its interesting

My girlfriend and I love strap on sex. I think she enjoys it as much as I do if not more. She loves how I moan like a slut wile she fucks my ass. She says hearing me moan is the biggest turn on for her. She also likes when i let her fuck me real hard to. She likes to hear our skin slapping together. I loves the way she looks wile wearing the strap on. So sexy! The dildo feels great sliding in and out of my ass and stretching me out. A lot of fun for both partys if it is done right with some one u love and trust.

love to try it with a woman ,have her love me that way see how it feels