I am 62. About fifteen years ago I could have written almost exactly what you have written above. I blew up my long term marriage because of my fucked up thinking. It was a horrible mistake and one that I regret essentially every day.
Of course, maybe it's all different for you. I mean that. I'm only suggesting something to check.
Have a look at the material under "Nice Guy Syndrome" by Dr. Robert Glover. [1] Maybe get his audio book "No More Mr. Nice Guy" and listen to it for a bit, and see how well it fits or does not fit your situation.