Ok. It's really sad reading this because the misalignment is big. She is ok with a companion she loves. You have needs beyond that. The dream she has is sad to read. It is never going to happen like this.
The idea sounds like a solution, yet, the reality is no way going to match this in my mind.
You can't answer this, but how on earth can your wife compartmentalise your shagging other ladies, not knowing who is calling, texting, reacting to every phone alert, where you are, how many there are, if you have feelings.
And you would eventually develop feelings. Then deceit and lying would destabilise the bedrock.
I want your wife to go access counselling and find the strength to realise this is not in her best interests at all. She is offering you something, in my opinion, based on vulnerability and fear of the unknown, being alone, something.
It is not fair on her. Because, it will end in tears I strongly believe. Her tears.
Have you thought why you are staying in the marriage when the intimacy sex drive is still high for you?
Why are you not looking to end this and move towards something new that better meets your needs? And I don't believe ' because I love her'. It is what she is doing for you that keeps you there.
Can you consider finding someone else to eventually fulfil that role or simply seeking sexual fulfillment whilst having an amicable separation from your wife on your initiation?