There is no easy way out, we all had to go through the same pain of losing a marriage , losing kids and losing hundreds of friends.
You cannot stay in and be miserable for the rest of your life. No matter what plan of exit you choose it won't be easy but needs to be done and not living a lie.
As said you will gain a life of freedom and searching of happiness your way and not the watchtower.
Good luck... you can do it.