MichaelM,
So much I could say but will agree with Di , don't make promises you can't keep . Also take care in suggesting it won't go any further , I came out to my wife in my forties like you and now in my sixties I'm separated and living full time .
We are all different but you may have to accept now you've come out it can go either way , I realise looking back that the damage was done when I told her . Try not to too hung up on the lies and deceit angle , I know what a tough choice it is , I'd almost ceased to function so my wife knew I was unhappy, OK the revelation wasn't quite what she expected .
I hope it does work out for you but I will add the alternative doesn't mean the World comes to an end , for me it's actually working out better for everyone rather than trying to hold a marriage together and walk on eggshells .