OK, then try looking
here.
Sorry, couldn't help myself. But, that's a list of reviews of movies; it'll give you a breakdown of the scenes, and give you an idea of if there is degrading stuff in it or not.
Of course, there are billions of porn videos released each week*, and your local store won't have most of them. So, go to the store, and look for videos made by Adam & Eve or Wicked Pictures. Write down the titles of the movies that look promising (sure, they'll look at you funny, but who cares). Look up the reviews at the site I linked above. Go back, rent porn, have sex with your wife.
If you are trying to introduce the MMF thing, perhaps keep a dildo around for having sex while watching the video? Also, some MMF scenes have simultaneous vaginal/anal penetration and some don't, I don't know which you are looking for, better read the reviews first.
* note: statisctics made up for effect
EDIT: Coppertop recommended Andrew Blake. I find his videos so artistic that they fail to be erotic. Just my opinion.