You said "he had clearly developed enough of a bond to really want to keep her in his life"
Sorry that's not how it works and this may make it easier to make the break.
He does not care for nor have a bond with this woman, she just hasn't spotted him for the waster he is and he will dangle her on the end of a long leash for as long as she will allow him to. There is no care here, she is just a convenient lay for him.
His only thought is for himself, not you and certainly not her. It''s nothing to do with his childhood or her personality, it's soley down to him not wanting to commit to anything so he will take anyone who is willing to give him time.
Like many others here, been there, done that.
Don't beat yourself up, he said and did all the right things in order to get you on his hook, that you noticed in such a short time while still in the rosy glow phase is remarkable. At his age he has had a great deal of practise so if anything you should have a gold star for spotting his ploy and talking to others about it.
Edited for spelling and add last paragraph