My wife and I want someone to fuck her

My wife doesn't like the idea of me with another woman as it brings back memories from when we first got together and I was messaging other woman behind her back (never did anything with the other woman) anyway it was a fantasy we spoke about and at first she stated it was degrading and she only wants my cock inside her otherwise it's cheating but after talking for a couple about it she got turned on by the idea and agreed to give it ago, she's not sure if she will go all the way with a man or if she will stop before getting to sex she said she would see how it makes her feel first which is fine by me, maybe if she likes it a lot and in time I maybe able to screw some blokes wife whilst he's screwing mine but that's just a bonus the main reason is I want her to be pleasured by another man whilst I watch!