DITTO, DITTO, DITTO, DITTO, DITTO, to everything you have said. The very, very, very toughest part is following through on leaving if things don't change.
The only thing I might add to this is that in the mother/son dynamic, I often think that the person who is the 'son' takes on this role as an attempt to keep control of the relationship... often in the same manner a child attempts to manipulate and control their parents.
As with HD, he is 'growing up' so to speak... and if he keeps his course, one of two things will happen... his W will either change or leave him, neither of which he can control, he can only control himself. But these are decisions of an adult, based upon decisions he's made for himself... and he OWNS that. Instead of constantly apologizing and cow-towing for who he is, HD is now (YES!!) becoming his own person.
SD, it is not a cruel thing to tell your wife the scoop on where you are. Is it not a crime to be feeling the way you feel... you are an adult, with your own wants/dreams/desires... if your W can't meet you half way, doesn't mean she is a bad person and you don't love her. IT ISN'T ABOUT HER. It's about you. It's YOUR life. You only have one. You can't live hers and yours... you can only live yours. You are free to be who and what you are, just as she is. You just have to be adult enough and have the courage to accept that. Love her enough to treat her as an adult and give it to her straight... just as you would to any other adult human being on the planet.
The very worst prisons that exist in this world are those we create ourselves, the ones that exist in our own minds.
You think you can only see maybe three possible outcomes to your sitch. All I can tell you is... until you actually DO something, you can't even FATHOM all the possibilities. You just will not see nor experience any of them until you take responsibility for your own life.