This is very common indeed, especially these days. As we both confessed that this lifestyle is something we both always dreamed we realised that at least one couple in our close relationship already living through this and so happy.
I think we had similar problem here at the very beginng, my wife is naturally jealous and she was in doubt for whom this once I slightly opened that topic. But once I fully confessed and showed how I love her and this lifestyle she finally managed to be open with me and confess that this is something she wanted to try for a long time too. And I truly believe that the majority of women want this naturally but if environment allows.
First time I realised that I have cuckolding nature is once we visited a nude resort where I could see how men starred at my wife. Some of them wanted to approach her and a few made a compliment. So quite a few times I struggled to hide my erection because of this.
I think for us one of the crucial point was to watch porn. Once I showed her MFM porn and I could notice straightaway how she was aroused although slightly ashamed so I did not mention anything but rather showed her how I became aroused. So next time despite being jealous she tried to "pay me back" and showed fmf, I really did not like it (neither my cock
) but rather found a good DP porn remarking "this is what we both like" and showed my rock solid penis. And then one day we watched gangbang when we managed both speak the truth.